DEPARTMENT OF THE INTERIOR 

Franklin K. Lane, Secretary 



United States Geological Survey 

George Otis Smith, Director 
WATER-SUPPLY PAPER 446 



GEOLOGY AND GROUND WATERS 

OF THE 

WESTERN PART OF SAN DIEGO COUNTY 
CALIFORNIA 



BY 



ARTHUR J. ELLIS and CHARLES H. LEE 



Prepared in cooperation with 

THE DEPARTMENT OP ENGINEERING OP THE STATE 

OF CALIFORNIA AND THE CITY OF SAN DIEGO 




WASHINGTON 

GOVERNMENT PRINTING OFFICE 

1919 



Monograph 



/ 



DEPARTMENT OF THE INTERIOR 

Franklin K. Lane, Secretary 



United States Geological Survey 

George Otis Smith, Director 



Water-Supply Paper 446 




GEOLOGY AND GROUND WATERS 

OF THE 

WESTERN PART OF SAN DIEGO COUNTY 
CALIFORNIA 



BY 



ARTHUR J. ELLIS and CHARLES H. £EE 



Prepared in cooperation with 

THE DEPARTMENT OF ENGINEERING OF THE STATE 

OF CALIFORNIA AND THE CITY OF SAN DIEGO 




WASHINGTON 

GOVERNMENT PRINTING OFFICE 
1919 



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0. 01 .-. 



CONTENTS. 



Page. 

Introduction 15 

History of ground-water utilization, by C. H. Lee 15 

Previous geologic work, by A. J. Ellis 17 

Purpose and scope of this investigation 18 

Acknowledgments 19 

Physiography, by A. J. Ellis 20 

Introductory statement , 20 

San Diego coastal belt 21 

General features 21 

Coast line 22 

Terraces 25 

General relations 25 

Poway Mesa : 28 

Mounds 29 

Ancient beach ridges 30 

San Onofre Hills 30 

Major valleys 31 

Santa Margarita Valley 31 

San Luis Rey Valley 31 

San Dieguito Valley.... 31 

Mission Valley 32 

Sweetwater Valley 32 

Otay Valley 32 

Tia Juana Valley 32 

Origin of major valleys 32 

Minor valleys 34 

The highland area 34 

General features 34 

The mountains ., 36 

General relations '. 36 

Origin 36 

River valleys 38 

San Luis Rey Valley 38 

San Dieguito Valley 38 

San Diego Valley 39 

Sweetwater and other valleys 39 

Peculiarities of drainage systems 39 

An ancient river valley 40 

Highland basins 41 

General features 41 

Lower belt 43 

Fallbrook Plain 43 

Escondido and Poway valleys . 44 

El Cajon Valley 45 

Origin of the basins of the lower belt 46 

3 



4 CONTENTS. 

Physiography, by A. J. Ellis— Continued. 
The highland area — Continued. 

Highland basins — Continued. p age . 

Intermediate belt 46 

Bear Valley 46 

Santa Maria Valley 47 

Other basins 47 

Higher belt 48 

Origin of highland basins .-... 48 

Geology, by A. J. Ellis , 50 

General statement 50 

Sedimentary formations 50 

Distribution and character 50 

Cretaceous system 51 

Chico formation 51 

Tertiary system 52 

Distribution 52 

Eocene series 53 

Miocene and Pliocene series 57 

San Onofre breccia 57 

San Diego formation 58 

Poway conglomerate 67 

Late Tertiary beach deposits 68 

Quaternary system 68 

Pleistocene series 69 

San Pedro formation 69 

Pala conglomerate 70 

Lacustrine deposits 70 

Recent series 71 

Valley fill , 71 

Residuum 71 

Igneous and metamorphic rocks 71 

Geologic history 74 

Pre-Cretaceous sedimentation 74 

Pre-Cretaceous or early Cretaceous diastrophism, volcanism, and 

metamorphism 74 

Cretaceous' (?) peneplanation 74 

Early Tertiary uplift, rejuvenated erosion, and coastal sedimentation. . 75 

Late Tertiary and Quaternary emergence and oscillation 75 

Precipitation, by C. H. Lee 76 

General conditions 76 

Character of storms 76 

Observations of precipitation 77 

Distribution of precipitation in time 85 

Geographic distribution of precipitation 87 

Relation of run-off to precipitation 90 

Summary 99 

Evaporation, by C. H. Lee 99 

Evaporation from water surfaces 99 

Evaporation from soil 104 

Method of discussing ground water by areas 105 



CONTENTS. 



Water in the major valleys, by C. H. Lee 106 

Topography and drainage 106 

Relation of valleys to adjacent areas 106 

Coastal valleys 107 

Highland valleys 108 

Surface waters 108 

Soils and vegetation 109 

Underground reservoirs 110 

Sources of water 110 

The valley fill *. Ill 

Coastal valleys Ill 

Origin of the deposits Ill 

Tia Juana Valley 112 

Sweetwater Valley .. 114 

Mission Valley 114 

San Dieguito Valley 116 

San Luis Rey Valley 116 

Santa Margarita Valley 117 

Highland valleys 119 

Upper Sweetwater Valley 119 

Upper San Diego River Valley 119 

San Pasqual Valley 120 

Upper San Luis Rey Valley 121 

Porosity 121 

The water table 123 

Form and slope 123 

Fluctuations of the water table 132 

Ground-water yield 142 

Economic requirements 142 

Average yield 143 

Replenishment of reservoirs 143 

Depletion of reservoirs 146 

Relation of replenishment to loss 149 

Method of computing annual additions to supply of ground 

water 149 

Accuracy of computations 151 

Safe yield 153 

Yield of wells . 155 

Conditions affecting yield 155 

Tests of yield of wells 158 

Purpose and methods of tests 158 

Results of tests : 159 

Well K 41 159 

Well L 82 159 

Well O 132 159 

Wells at Mission Valley pumping plant of San Diego city. . 160 

Discussion of well tests 162 

Method of sinking wells 164 

Water in minor valleys, by A. J. Ellis and C. H. Lee 166 

Distribution of minor valleys 166 

Minor valleys of the coastal belt 167 

Topography. 167 

Materials of the fill 167 



6 CONTENTS. 

Water in minor valleys, by A. J. Ellis and C. H. Lee — Continued. 

Minor valleys of the coastal belt — Continued. Page. 

Water table 168 

Ground- water yield 168 

Wells 169 

Wells between Oceanside and Delmar. 169 

Wells in McGonigle Canyon 171 

Wells between Los Penasquitos Canyon and Mission Valley 171 

Wells in Soledad Canyon 172 

.Wells in San Clemente Canyon 173 

Wells south of Mission Valley 174 

Minor valleys in the highland area 174 

Topography 174 

Materials of the valley fill 175 

Water table 175 

Ground- water yield 175 

Water in Tertiary and older sedimentary formations, by A. J. Ellis and C.H.Lee 175 

Water-bearing capacity of the formations 175 

San Onofre Hill district 176 

Tertiary gravel tracts 177 

Linda Vista Terrace district 177 

General conditions 177 

Wells on the high terraces 178 

Deep wells ending in sedimentary rocks under valley fill 180 

Nestor and Chula Vista terraces 181 

Sources of water 181 

Yield of wells 183 

Conditions affecting yield 183 

Interference of wells 184 

Well tests 186 

Well O 115 186 

Well O 47 186 

Well O 102 187 

Discussion of tests 187 

Well construction 187 

Ground water in the highland area, by A. J. Ellis and C. H. Lee 189 

Water-bearing formations 189 

Water in the crystalline rocks 189 

Water in the talus 190 

Water in the residuum 191 

Character of the residuum - 191 

Water table 192 

Sources of water 193 

Yield of wells 193 

Methods of sinking wells in residuum 194 

Descriptions by areas 196 

Fallbrook and vicinity 196 

Escondido and vicinity 197 

Poway Valley 199 

Ramona and vicinity - 200 

El Cajon Valley 201 

Padre Barona Valley 202 

Warners Valley 203 

San Felipe Valley 206 



CONTENTS. 



Detailed well records 208 

Quality of water, by A. J. Ellis 222 

Scope of work 222 

Methods of analysis and accuracy of results 222 

Standards for classification 223 

Mineral constituents of water 223 

Water for domestic use 224 

Physical qualities 224 

Bacteriological qualities 224 ■ 

Chemical qualities 225 

Mineral matter and potability 1 226 

Interpretation of analytical data in relation to potability 227 

Chemical character 227 

Total solids ■ 228 

Water for irrigation 229 

Source of alkali 229 

Occurrence of alkali 229 

Permissible limits of alkali 230 

Relative harmfulness of the common alkalies 232 

Relation between applied water and soils 233 

Numerical standards 234 

Remedies for alkali troubles 236 

Washing down the alkali 236 

Drainage 238 

Miscellaneous remedies 238 

Water for boiler use 239 

Formation of scale 239 

Corrosion -. 239 

Foaming 240 

Remedies for boiler troubles 241 

Boiler compounds 241 

Numerical standards 243 

Water for miscellaneous industrial uses 246 

General requisites 246 

Effects of dissolved and suspended materials 247 

Free acids 247 

Suspended matter 247 

Color 248. 

Iron 248 

Calcium and magnesium 248 

Carbonate 249 

Sulphate 249 

Chloride 249 

Organic matter 250 

Hydrogen sulphide 250 

Miscellaneous substances 250 

Quality in relation to geologic source 250 

General relations 250 

Water from residuum 251 

Water from Tertiary and other sedimentary formations 253 

Water from valley fill 255 

Quality in relation to use for irrigation 258 

Quality of surface waters 259 



8 CONTENTS. 

Page. 

Tests of pumping plants, by C. H. Lee 264 

Purpose of tests _ 264 

Methods used in tests 265 

Equipment 265 

Measurements and computations 265 

Discharge 265 

Head 266 

Speed 266 

Water horsepower 266 

Power input 267 

Horsepower input at pump 267 

Plant efficiency 267 

Results of tests 267 

Pumping plant at well O 132 267 

Pumping plant at well K 41 268 

Pumping plant at well O 115 269 

Pumping plant at well 47 270 

Pumping plant at well O 102 271 

Pumping plant at well L 24 272 

Pumping plant at well L 98 273 

Discussion of tests and cost of pumping 274 

Estimates of fixed charges 274 

Pump efficiency 276 

Plant efficiency 277 

Cost of pumping 277 

Selection and installation of pumping plants 279 

General considerations 279 

Pumps 280 

Capacity of pump 280 

Type of pump 281 

Classification of types 281 

Power plunger pumps 282 

Deep- well reciprocating pumps 282 

Centrifugal pumps 282 

Power 284 

Type of power 284 

Size of engine or motor 285 

Piping and connections 285 

Convenient equivalents 287 

Publications consulted 288 

Physiography, geology, and ground water 288 

Pumping plants 289 

Index 315 



ILLUSTRATIONS. 



Plate I. Sketch map of part of California, showing areas treated in the pres- 
ent report and in other water supply papers of the United States 

Geological Survey relating to ground water 16 

II. Map of the San Diego County area, Calif., showing topography and 

location of wells In pocket. 

III. Preliminary geologic map of western part of San Diego County, 

Calif In pocket. 

IV. A, Diabase dike in Eocene sediments at La Jolla; B, Sea cliffs of 

Cretaceous rocks (Chico formation) at La Jolla 22 

V. A, West edge of Linda Vista Mesa, near Encinitas;!?, Beach pebbles 

deposited by stranded sea weed, Encinitas 23 

VI. Map of San Diego quadrangle, Calif., showing marine terraces and 

marine soundings In pocket. 

VII. Topographic map of part of La Jolla quadrangle showing erosional 

features of Linda Vista and Poway terraces 28 

VIII. Mounds on Linda Vista terrace 30 

IX. Santa Margarita River valley before the flood of January, 1916 32 

X. Santa Margarita River valley after the flood of January, 1916 32 

XI. Landslide in wall of Mission Valley 33 

XII. Small fault exposed at the Himalaya mine, near Mesa Grande 38 

XIII. El Cajon Valley,- looking northeast from Grossmont 39 

XIV. A, Pala conglomerate at Pala; B, Porphyritic dike cutting Tertiary 

sediments, Los Penasquitos Canyon 50 

XV. Map of western part of San Diego County, showing precipitation 

and drainage areas above gaging stations In pocket. 

XVI. Diagrams showing duration, intensity, and total precipitation of 

storms at typical stations in San Diego County in 1914-15 86 

XVII. Diagrams showing variation in annual precipitation at nine control 

stations in San Diego County 86 

XVIII. Diagrams showing influence of topography, location, and altitude 

on precipitation in San Diego County 88 

XIX. Daily hydrographs of principal streams in San Diego County, 

1914-15 In pocket. 

XX. Map of southern part of San Diego Bay region, showing principal 
water-bearing formations, contours of the water table, observation 

wells, and tested pumping plants 106 

XXI. Map of Mission Valley, showing principal water-bearing formations, 
contours of the water table, observation wells, and tested pumping 

plants 1 106 

XXII. Map of El Cajon Valley and vicinity, showing principal water- 
bearing formations, observation wells, and tested pumping 

plants In pocket. 

9 



10 



ILLUSTKATIONS. 



Page. 
Plate XXIII. Map of San Dieguito Valley, showing valley fill and location 

of observation well and gaging station 108 

XXIV. Map of San Pasqual and Santa Maria valleys, showing prin- 
cipal water-bearing formations and observation wells 108 

XXV. Map of San Luis Rey and Santa Margarita valleys, showing prin- 
cipal water-bearing-formations and observation wells. . . In pocket. 

XXVI. Sections of wells in Tia Juana Valley 112 

XXVII. Sections of wells in San Diego formation in vicinity of San 

Diego Bay 112 

XXVIII. Sections of wells in Mission Valley 116 

XXIX. Sections of wells in upper San Diego River valley 120 

XXX. Longitudinal profile of Mission Valley, showing fluctuation 

of water table In pocket. 

XXXI. Section across Mission Valley at Old Town pumping plant, 

showing fluctuation of water table 132 

XXXII. Longitudinal profile of upper San Diego River valley, 
showing position of water table in different seasons of the 
year, 1914-15; also profile of surface of water table in 

vicinity of Lindo Lake In pocket. 

XXXIII. Section across upper San Diego River valley at Monte 
pumping plant, showing fluctuation of water table and 

plan of pumping plant . 132 

XXXIV. Longitudinal profiles of Tia Juana Valley, showing fluctua- 
tions of water table 132 

XXXV. Section from Tia Juana Valley to National City, showing 

fluctuations of water table, 1914-1915 In pocket. 

XXXVI. Diagrams showing fluctuation of water table in observation 

wells in Tia Juana Valley In pocket. 

XXXVII. Diagrams showing fluctuation of water table in observation 

wells in Sweetwater Valley 134 

XXXVIII. Diagrams showing fluctuation of water table in observation 

wells in Jamacho and Dehesa valleys 134 

XXXIX. Diagrams showing fluctuation of water table in observation 

wells in Mission Valley In pocket. 

XL. Diagrams showing fluctuation of water table in observation 

wells in upper San Diego River valley 138 

XLI. Diagrams showing fluctuation of water table in observation 

wells in San Pasqual and San Dieguito valleys In pocket. 

XLI I. Diagrams showing fluctuation of water table in observation 

wells in San Luis Rey Valley In pocket. 

XLIII. Diagrams showing fluctuation of water table in observation 

wells in fill of minor valleys 168 

XLIV. Sections across Otay Valley and parallel to it, showing fluc- 
tuation of water table In pocket. 

XLV. Diagrams showing fluctuation of water table in observation 

wells in San Diego formation in vicinity of San Diego Bay. 184 
XLVI. Section through Nestor terrace, showing fluctuation of water 

table In pocket. 

XLVI I. Diagrams showing fluctuation of water table in observation 

wells in granite areas 192 

Figure 1. The Tecolote drainage system, showing angular courses of minor 

streams produced by ancient beach ridges on Linda Vista Mesa. . 34 
2. Sketch showing topography of Santa Maria Valley in vicinity of 

Ramona; from photograph by M. R. Campbell 42 



ILLUSTRATIONS. H 



Figure 3. Relation of length of record of precipitation to variation from the 

average at San Diego 82 

4. Relation of length of record of precipitation to variation from the 

average at Escondido 83 

5. Monthly distribution of precipitation in San Diego County 86 

6. Relation of altitude to long-term average annual precipitation for 

all stations in San Diego County 89 

7. Variation in annual discharge of streams in San Diego County 91 

8. Comparison of evaporation with temperature and precipitation at 

Sweetwater dam 100 

9. Diagrammatic cross section of Tia Juana Valley along line E-E, 

Plate XX 112 

10. Diagrammatic cross section of Tia Juana Valley along line F-F, 

Plate XX 113 

11. Diagrammatic cross section of Mission Valley along line B-B, 

Plate XXI 114 

12. Diagrammatic cross section of Mission Valley along line A-A, 

Plate XXI 115 

13. Diagrammatic longitudinal section of San Diego River valley 116 

14. Diagrammatic cross section of San Luis Rey Valley along line A-A, 

Plate XXV 117 

15. Sections of wells in upper San Luis Rey and upper Sweetwater 

valleys 118 

16. Plan of Mission Valley pumping plant of the city of San Diego 160 

17. Diagram showing digitate character of contact between talus slope 

and valley fill; conditions favorable for rapid drainage of talus. . 190 

18. Sections of wells in residuum 192 



TABLES. 



1. Sedimentary formations in the San Diego area, California 51 

2. Log of Clark oil well 55 

3. Log of Balboa oil well 55 

4. Log of Balboa oil well, 1913 56 

5. Log of well on Point Loma 61 

6. Log of L. K. Lanier's well 62 

7. Log of Robert Dick's well 62 

8. Log of Angelus Heights well 63 

9. Log of test well No. 1, Chula Vista Oil Co 64 

10. Log of test well No. 2, Chula Vista Oil Co 65 

11. Log of test well No. 3, Chula Vista Oil Co 65 

12. Log of test well No. 4, Chula Vista Oil Co 65 

13. Log of Chula Vista oil well '. 66 

14. Log of Lo Tengo Oil Co. 's well 67 

15. Log of Tia Juana oil well 67 

16. Log of Beaver oil well 68 

17. Summary of precipitation records in San Diego County 79 

18. Precipitation index and annual variation of precipitation at nine control 

stations in San Diego County, expressed as per cent of average observed 

precipitation 84 

19. Precipitation required to produce flood run-off in typical streams of San 

Diego County 93 

20. Run-off from and precipitation on drainage basins of streams in San Diego 

County 95 

21. Average depth of precipitation, in inches, required to produce run-off 97 

22. Monthly discharge, in acre-feet, of Escondido Mutual Water Co's. canal 

at heading near Nellie, 1904-1915 97 

23. Annual discharge of San Luis Rey River near Pala, including Escondido 

Mutual Water Co's. canal, 1904-1915 98 

24. Summary of data showing ratio, in percentage, of run-off to precipitation 

on drainage area 98 

25. Evaporation from free water surface at Sweetwater reservoir, 1889-1892 . . . 101 

26. Evaporation from free water surface at La Mesa reservoir 102 

27. Evaporation from free water surface at Cuyamaca reservoir 102 

28. Comparison of depths of evaporation measured by floating pan at La Mesa 

reservoir with those computed from reservoir levels atupper Otay reservoir. 103 
2.9. Areas of drainage basins tributary to streams at gaging stations in San 

Diego County 109 

30. Summary of observations of water level at wells in San Diego County dur- 

ing season of 1914-15 126 

31. Summary of observations of water level at wells in San Diego County, 

1912-1915 130 

32. Annual range of fluctuations of water level in record wells in San Diego 

County, 1914-15 133 

33. Annual range of fluctuations, in feet, of water level in record wells in San 

Diego County, 1912-13 to 1914-15 133 

12 



TABLES. 13 



34. Duration of flow of principal streams in San Diego County at typical gaging 

stations .' 136 

35. Time required for water table to reach maximum levels after first storm 

producing run-off 140 

36. Summary of data showing duration of flood flow, in days for principal rivers 

of San Diego County 144 

37. Comparative discharge measurements of principal streams of San Diego 

County, made in 1914-15 145 

38. Monthly discharge, in acre-feet, at gaging stations on three rivers in San 
Diego County for period June to December, 1914, following a rainy season 

in which run-off was less than the average 147 

39. Monthly discharge, in acre-feet, at gaging stations on three rivers in San 

Diego County, for the period June to September, 1915, following a rainy • 
season in which run-off exceeded the average 147 

40. Observed and computed data regarding ground-water intake in major 

valleys of San Diego County 151 

41. Estimated annual safe yield of ground water available for domestic and 

municipal supplies from major valleys of San Diego County 154 

42. Summary of tests of San Diego city wells at Mission Valley pumping plant. . 161 

43. Summary of tests of typical wells in San Diego County 162 

44. Depth to water level in test holes on the Warner ranch 203 

45. Wells in San Diego County in which series of water-level measurements 

were made 209 

46. Records of all wells and springs that were examined in San Diego County. . 221 

47. Factors for computing reacting values 228 

48. Rating of waters by total solids 228 

49. Effect of flooding on alkali, as shown by composition of water , 237 

50. Ratings of waters for boiler use according to proportions of incrusting, cor- 

roding, and foaming constituents 244 

51. Comparison of quantities of total dissolved solids in waters analyzed from 

different geologic sources 251 

52. Partial analyses and classification of two samples of water from uncontami- 

nated residuum 252 

53. Partial analyses and classification of waters of extreme types from Tertiary 

deposits 255 

54. Average quantities of certain constituents in 17 waters analyzed from Ter- 

tiary and older formations 255 

55. Average quantities of certain constituents in waters analyzed from valley 

fill in coastal belt and in highland basins 257 

56. Partial analyses of surface waters 259 

57. Partial analyses and classification of water from wells and springs 260 

58. Laboratory assays and classification of water from wells 262 

59. Incomplete laboratory assays of water from wells and springs 263 

60. Assumed fixed charges for pumping plants 274 

61. Summary of pumping plant tests and cost of pumping 275 

62. Conversion table — Rates of flow 287 

63. Conversion table — Pressure units 287 

64. Monthly and annual precipitation at 106 stations in or near San Diego 

County 290 



GEOLOGY AND GBOUND WATEBS OF THE WESTERN PART 
OF SAN DIEGO COUNTY, CALIFORNIA. 



By Arthur J. Ellis and Charles H. Lee. 



INTRODUCTION. 

HISTORY OF GROUND-WATER UTILIZATION. 

By C. H. Lee. 

According to the irrigation census taken in 1910 under cooperative 
agreement between the Bureau of the Census and the Department of 
Engineering of the State of California, 9,297 irrigation pumping plants 
were in operation in California during that year and 277,000 acres were 
irrigated by pumping from wells. In 1914 the number of pumping 
plants in the State had increased to 24,589/ and if the area irrigated 
from such plants had increased in the same proportion, it was in that 
year approximately 700,000 acres. The total area irrigated from 
surface and ground waters in California in 1914 was about 3,200,000 
acres. 2 The data therefore indicate that ground water served nearly 
one-fourth of the irrigated lands of the State at that time, and it fur- 
nishes a far greater part of the water used for domestic, manufactur- 
ing, and municipal supplies. 

In San Diego County (PL I) extensive utilization of the ground 
waters was begun only a few years ago, and much additional develop- 
ment is still possible. The potential demand probably exceeds that 
in any other settled part of the State. Irrigation is necessary for the 
successful cultivation of most of the agricultural crops to which the 
climate and soil of the region are adapted. Furthermore, the climatic 
and scenic features of much of the county make it very attractive as 
a place of either temporary or permanent residence. As the delightful 
climate of the San Diego coast becomes more widely known, the region 
will undoubtedly become one of the most popular playgrounds of the 
United States, drawing upon the heated regions of the Southwest 
during the summer and the Eastern and Northern States during the 
winter. There will also be an ever-increasing permanent popula- 
tion. The demand for water for household and garden uses is 
already large and is destined far to exceed the demand for water for 
irrigation in commercial agriculture. 

1 Adams, Frank, Progress report of irrigation investigations * * * in California, 1912-14: In Cali- 
fornia Itept. of Engineering Fourth Bien. Kept., Dec. 1, 1912, to Nov. 30, 1914, pp. 158-210, 1914. See pp. 
177-1.7$. 

2 3,196,000 acres in 1912: Idem, p. 207. 

15 



16 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

The surface waters, though at times overwhelming in volume, are 
unfortunately not dependable and require expensive storage and 
transmission works for their utilization. There are no perennial 
streams except at high levels and at a considerable distance from the 
coast where they are too small to be of much practical value. Pre- 
cipitation of sufficient magnitude to produce run-off is confined to 
three or four months of the year, and in years of average precipitation 
the larger streams do not maintain a permanent flow for more than five 
or six months. To obtain from the surface streams the unfailing 
water supplies required for irrigation and especially for domestic uses, 
it is necessary to provide large storage reservoirs. Conditions are 
made even more unfavorable by the wide variations in precipitation 
from one year to another and by the occasional periods of severe 
drought. This condition necessitates holding in reserve sufficient 
water (in storage) to supply the full requirements for a three or four 
year period. The expense of providing the necessary storage works is 
great, and after the water has been stored the losses by evaporation 
from the exposed water surface may amount to a large proportion of 
the volume originally stored. The problem of keeping water up to a 
standard of potability for domestic use after being held in storage for 
two or three years is also very difficult. 

On the other hand, supplies of ground water, if available at all, 
are relatively reliable, especially if they are drawn upon only to 
supplement surface supplies. They are also protected from evapo- 
ration and can be more easily protected from pollution. 

Ground water was first largely used in San Diego County in 1898 — 
the first year of serious drought subsequent to the early eighties, 
when the extensive settlement of the county was begun. This 
drought continued with varying severity until 1905, rainfall and 
stream flow being far below normal throughout the whole period. 
Large consumers of water at that time were the communities of 
Chula Vista and National City, supplied from Sweetwater Reservoir, 
which was built and operated by the San Diego Land & Town Co., 
the orchard and farm lands supplied by the San Diego Flume Co. 
from storage and gravity flow of San Diego River, and the city of 
San Diego, supplied by San Diego flume and other sources. In the 
effort to serve these consumers when the surface waters failed wells 
were sunk and pumping plants installed at the nearest sites that 
gave promise of yielding adequate quantities of water. The San 
Diego Land & Town Co. sank batteries of wells at a number of points 
in the valley of Sweetwater River; the San Diego Flume Co. installed 
two plants in the upper San Diego River valley above Lakeside; 
the city of San Diego drew from several batteries of wells in Mission 
Valley; and many orchardists endeavored to augment from small 
plants on their own lands the inadequate supplies furnished by the 



U. S. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 446 PLATE : 




SKETCH MAP OF PART OF CALIFORNIA 

Showing areas treated in the present report and in other water-supply papers of the U. S. Geological Survey relating to ground water 



INTEODUCTION. 17 

companies. With the return of normal conditions of stream flow 
in 1905, the use of the larger pumping plants was discontinued and 
most of the equipment was removed, and the use of many of the 
private plants that had been but moderately successful was also 
discontinued. 

Activity in the settlement and development of the county was not 
renewed until about 1909, and in the interval rapid strides had been 
made in the manufacture of cheap, efficient pumping equipment. 
The river valleys, with their ample stores of ground water and low 
pumping lifts, offered attractive agricultural opportunities for small 
land owners. In the period beginning with 1909 much of the Tia 
Juana, Otay, Sweetwater, and ^San Diego river valleys was put 
under cultivation by irrigation from individual pumping plants. 
A few of the many efforts that were made to obtain irrigation water 
outside the river valleys were moderately successful, but only in 
the major valleys have supplies adequate for the irrigation of large 
areas been developed. Nevertheless there remains much additional 
land in small tracts outside the major valleys that can be irrigated 
from ground waters obtained locally. 

The importance of ground water as a reserve in periods of drought 
makes accurate knowledge of the quantity available essential to 
permanent settlement. For instance, the over use of ground water 
to irrigate an orchard in the early periods of a protracted drought 
might make it impossible later in the period to obtain enough 
water to keep the fruit trees alive or even to supply the domestic 
needs of the owners. The investigations here reported were made 
not only for the purpose of suggesting where and how ground 
waters can be obtained, but also to indicate the limits to which 
supplies of ground water should be utilized. 

PREVIOUS GEOLOGIC WORK. 

By A. J. Ellis. 

The earliest geologic survey of this region was that conducted by 
C. C. Parry and Arthur Schott, in connection with the United States 
and Mexican Boundary Survey. 1 From July, 1849, to March, 1851, 
Dr. Parry was in the vicinity of San Diego, and resided during the 
fall and winter of 1850-51 at San Luis Key. His excursions extended 
northward along the coast to Monterey and eastward to Gila River, 
and embraced the region then known as southern California. Parry's 
collections of rock specimens and fossils were classified and described 
by James Hall 2 and T. A. Conrad. 3 

1 Parry, C. C, and Schott, Arthur, Geological reports: United States and Mexican Boundary Survey, vol. 
I, part 2, pp. 1-98, 1857. 4 

a Hall, James, Paleontoldgy and geology of the boundary: United States and Mexican Boundary Survey 
vol. 1, part 2, pp. 103-140, 1857. 

» Conrad, T. A., Description of Cretaceous and Tertiary fossils: Idem, pp. 141-147. 

115536°— 19— wsp 446 2 



18 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

The first geological survey of California was conducted during the 
years 1851 to 1856 by Dr. John B. Trask, but San Diego County was 
not included in the areas investigated. 

In December, 1853, William P. Blake, as geologist of the expedition 
under Lieut. E. S. Williamson, Corps of Topographical Engineers, 
to ascertain the most practicable and economical route for a railroad 
from Mississippi Kiver to the Pacific Ocean, traveled from San Felipe 
to San Diego and thence north to San Pedro, and made a report on 
the geology of the .region based on observations along his route. 1 
J. S. Newberry, geologist of the expedition under Lieut. J. C. Ives for 
the exploration of the Colorado River, crossed from San Diego to 
Yuma in December, 1857, and obtained notes on the geology. 2 

Under the second State geological survey of California in 1872, 
W. A. Goodyear made a reconnaissance of San Diego County, 3 and in 
1892 H. W. Fairbanks made an accurate reconnaissance survey of 
this and adjacent counties. 4 

All reports of the California State Mining Bureau subsequent to 
the fifth contain notes on the mineral resources of San Diego County, 
including observations on the general geology. In 1914 that bureau 
published a pamphlet by Dr. F. J. H. Merrill giving a general outline 
of the geology of San Diego and Imperial counties. 5 Some studies 
of the paleontology and stratigraphy of the coast have been made to 
which specific reference will be made in the following pages. 

PTJBPOSE AND SCOPE OF THIS INVESTIGATION. 

The area described in this paper comprises approximately that part 
of San Diego County which is drained directly into the Pacific Ocean. 
With unimportant exceptions, it does not include that part of the 
county whose streams discharge into an interior basin or into the 
Gulf of California. (See Pis. I and II.) The eastern limits of the 
area covered are, however, not sharply defined. Plates II, III, 
and XV (in pocket), which show topography, locations of wells, 
geology, and precipitation, cover the area lying west of longitude 
116° 30' and south of latitude 30° 30'. This area is about 60 miles 
long and 50 miles wide and embraces about 3,000 square miles. 

i Blake, Wm. P., Geological report, explorations and surveys for a railroad route from the Mississippi 
River to the Pacific Ocean: 33d Cong., 2d sess., S. Doc. 78, pp. 122-130, 176, 1856. Also Observations on the 
physical geography and geology of the coast of California from Bodega Bay to San Diego: United States 
Coast Survey Rept., 1855, pp. 376-398, 1856. 

2 Newberry, J. S., Geological report: In report upon the Colorado River of the West, explored in 1857 and 
1858 by Lieut. J. C. Ives under the direction of the Office of Explorations and Surveys: 36th Cong., 1st sess., 
H. Doc. 90, pp. 13-18, 1861. 

8 Goodyear, TV. A., San Diego County: California State Min. Bur. Eighth Ann. Rept., pp. 516-528, 1888. 

* Fairbanks, H. W., Geology of San Diego County; also of portions of Orange and San Bernardino coun- 
ties: California State Min Bur. Eleventh Rept., pp. 76-120, 1893. 

5 Merrill, F. J. H., Geology and mineral resources of San Diego and Imperial counties: California State 
Min. Bur., 1914. 



INTRODUCTION. 19 

The investigation on which this report is based was made under the 
direction of O. E. Meinzer, geologist in charge of the ground-water 
investigations of the United States Geological Survey, in financial 
cooperation with the State of California and the city of San Diego. 
The purpose was to obtain accurate and comprehensive information 
with regard to the ground waters of the western part of San Diego 
County available for use by landowners, water companies, and 
communities in the solution of their water-supply problems. 

The field work was begun in September, 1914. The geologic survey 
was made from September to December of that year. The observa- 
tions on ground water were continued without interruption until 
August, 1915, but data were not systematically gathered after De- 
cember, 1915, and any changes brought about by the floods of Jan- 
uary and February, 1916, have not been considered in this report. 
The important conclusions of the report are, however, not affected 
by these floods. 

In addition to the study of the geology and physiography of the 
area the field work included measurements referred to sea level of 
the water levels in wells; observations of flow of Tia Juana River 
near Nestor; measurements at irregular intervals of other streams; 
tests of typical wells and pumping plants; collection of information 
concerning other wells and pumping plants and of the materials pene- 
trated by wells; tests of porosity of water-bearing deposits; collec- 
tion of records of precipitation and evaporation and of general infor- 
mation pertaining to the development and use of ground water 
throughout the county ; and the collection of water samples. 

Most of the analyses of water were made by S. C. Dinsmore, under 
contract with the United States Geological Survey; others were made 
in the water-resources laboratory of the Survey. The analyses were 
classified and interpreted by Alfred A. Chambers, who also rendered 
much assistance in the preparation of the chapter relating to the 
quality of the waters. 

Measurements of the flow of the streams in the region and of the 
water levels in certain wells have been made for a period of years by 
the United States Geological Survey in cooperation with various 
agencies. Most of this work has been done by F. C. Ebert, under 
the direction of H. D. McGlashan, district engineer. The complete 
records of stream flow are published in a separate volume (Water- 
Supply Paper 447) , but use has been made of the records in the 
ground-water investigations reported in this paper. 

ACKNOWLEDGMENTS. 

K. B. Sleppy, assistant engineer, and D. L. Lee assisted in gathering 
and compiling the records pertaining to wells, stream flow, and pre- 
cipitation, and in collecting the samples of water for analysis. The 



20 GKOUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

pumping tests were made by W. R. Layne, assistant engineer. 
Assistance in the study of these tests and in the preparation of the 
discussion thereon was rendered by Raymond Matthew, assistant 
engineer. 

The writers wish to acknowledge the public spirit and interest 
shown by the officers of the city of San Diego, the Cuyamaca Water 
Co., Volcan Land & Water Co., Sweetwater Water Co., San Diego 
Consolidated Gas & Electric Co., and other organizations in furnishing 
data and in otherwise expediting the work. Acknowledgments are 
especially due to Mr. W. S. Post, chief engineer for the first two com- 
panies mentioned, Mr. R. T. Hill, geologist, Mr. H. A. Whitney, 
hydraulic engineer, department of water of the city of San Diego, 
Mr. John F. Covert, engineer for the Sweetwater Water Co., Mr. A. E. 
Holloway, of the San Diego Consolidated Gas & Electric Co., Mr. 
Rudolph Wueste, of the same department, and Mr. C. S. Alverson, 
hydraulic engineer, Mrs. M. J. Herman, Dr. W. E. Wisecup, Capt. 
J. F. Scott, and Mr. Wilkes James, for their cooperation and for the 
valuable information which they furnished. The writers are also 
very much indebted to Mr. A. E. Hatherly, of San Diego, for the com- 
plete logs w T hich he furnished for wells that he has drilled in Tia 
Juana, Otay, Mission, and other valleys and on the mesa in the vicinity 
of Nestor. The cooperation of the owners of w T ells and pumping 
plants in permitting measurements to be made was of great assistance 
in the work and is hereby acknowledged, together with their many 
other courtesies. Credit for specific information is given in the 
appropriate places in the text. 

PHYSIOGRAPHY. 

By A. J. Ellis. 
INTRODUCTORY STATEMENT. 

The part of San Diego County described in this report consists of a 
mountainous highland area and a narrow belt along the shore char- 
acterized by broad, flat-topped sea terraces, called in this report the 
San Diego coastal belt. The highland area is a part of a great upland 
region that extends far south into Lower California. This upland 
is limited on the east by a steep descent to the Gulf of California and 
the Salton basin, but its plateau-like surface slopes gradually west- 
ward toward the ocean. It appears like a huge block of the earth's 
crust that has been broken and uplifted along its eastern side. In 
form and position it resembles the Sierra Nevada, but the amount 
of uplift and tilting has been much less. 



PHYSIOGRAPHY. 21 

SAN DIEGO COASTAL BELT. 
GENERAL FEATURES. 

The coastal belt consists, for the most part, of several relatively 
flat, high, upland benches or terraces that are dissected by stream 
channels and that extend from the highlands westward to the ocean, 
where, except in the region of San Diego Bay, they terminate in a 
line of sea cliffs. The terraces are generally referred to collectively 
as "the mesa," but some of the interstream areas have received 
individual names, such as Otay Mesa, which lies between Tia Juana 
and Otay rivers, and Linda Vista Mesa, which extends from San 
Diego River to Los Penasquitos River. 

The major stream valleys are wide and flat bottomed and are 
bounded by very steep slopes that in many places are several hundred 
feet high. The minor stream valleys are the valleys of young streams 
that, with few exceptions, rise on the mesa. They are short, narrow 
gashes in the terraces and are tributary to the main streams or open 
directly into the sea. The major valleys are occupied by older rivers 
that head far back in the highland area. 

North of Mission Bay and rising high above the mesa Soledad 
Mountain forms a broad peninsula that extends a few miles into the 
ocean; south of Mission Bay, Point Loma forms a second peninsula 
that partly incloses San Diego Bay. 

From La Jolla (see map, PI. II, in pocket) the coast line extends 
northward, bearing gradually more and more to the west without 
any considerable irregularities ; but south of La Jolla it winds about 
bays and peninsulas so that the distance from La Jolla to the inter- 
national boundary measured along the shore is more than 75 miles, 
whereas the distance between these points in a direct line is less than 
25 miles. The total length of the shore line in San Diego County, 
including the bays, is about 125 miles, although the distance in a 
direct line from the southwest corner of the county to San Mateo 
Point at the northwest corner is only 68 miles. 

The controlling influence in the development of the physiographic 
features of the coastal belt has been oscillation — that is, the rising 
and sinking of the land with respect to the sea level. Such vertical 
movements of the land seem to have been almost continuous since 
the oldest sedimentary formations in the coastal belt were laid down. 
As a result of these movements deep valleys have been cut repeatedly 
by the streams and subsequently partly filled, and different levels 
have been successively exposed to the waves, so that numerous 
terraces have been formed. As described in more detail on page 
22, these movements have been irregular, being rapid at some periods 
and slow at others. At times they have affected only certain parts 
of this region; at other times the whole coastal belt in San Diego 



22 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

County seems to have moved uniformly. Within very recent geologic 
time the land has stood considerably higher than at present, and 
there are indications (see p. 23) that along most of the coast sinking 
is now in progress. The net result of these oscillations, however, has 
been a general elevation of the region. 

COAST LINE. 

From San Onofre to the mouth of Soledad Valley the coast line is 
bordered by cliffs which in places rise sheer from the margin of the 
water and in other places are separated from the water by a narrow 
band of beach sand. These cliffs have been formed by the waves 
cutting into and undermining a terrace that stands 75 to 100 feet 
above sea level. (See PL Y,A.) From the mouth of Soledad Valley 
to La Jolla the lower terrace is absent and the cliffs, which here mark 
the edge of Linda Vista Mesa, reach heights of more than 400 feet. 

Nine streams reach the sea between San Mateo Point and La Jolla. 
The lower parts of all their valleys have broad, flat, marshy bottoms 
and contain lagoons that on drying up in summer leave broad tracts 
heavily coated with salt. These lagoons lie where beach ridges have 
been built across the mouths of the valleys by waves and shore 
currents, so that most of them are entirely cut off from the ocean, 
and their drainage, except in times of flood, reaches the sea. by per- 
colation through the sand. Only the Santa Margarita, the San Die- 
guito, and the Soledad are able to keep narrow channels open through 
the beach deposits. 

The beach ridges, cliffs, and terraces are the results of wave erosion 
and deposition by shore currents, together with changes in the eleva- 
tion of the land with respect to sea level. The mode of their develop- 
ment may be illustrated by a brief discussion of the physiographic 
history of the area about Oceanside. Before the materials that form 
the 75 to 100 foot terrace bordering the coast near Oceanside were 
deposited the land stood possibly as much as 200 feet higher than it 
does at present. At that time the shore was no doubt somewhat 
farther west. While the land was rising and while it stood at this 
highest elevation the streams cut their valleys down to what was 
then sea level — that is, about 200 feet below the present valley floors. 
The land then sank to a level about 100 feet below that at which it 
now stands, so that the sea advanced over the lowlands and flooded 
the valleys. During this time of submergence the waves cut into the 
ends of the ridges between the estuaries and formed a line of sea 
cliffs with a wave-cut terrace at the base. Part of the material 
derived from this cutting was washed out into deeper water by the 
undertow and part was swept along shore and formed bars across the 
mouths of the estuaries in the same way that bars have been formed 
along the present shore. At the same time the streams were washing 



U. S. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 446 PLATE IV 




A. DIABASE DIKE IN EOCENE SEDIMENTS AT LA JOLLA. 




B. SEA CLIFFS OF CRETACEOUS ROCKS (CHICO FORMATION) AT LA JOLLA. 
Shows caves produced by wave erosion. 



TJ. S. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 446 PLATE V 



-..,-•* _■ - .- 
' *• - ~ - - ; -• 

' - - *_— _ ■ " „ ~'' 

...".■'■.''■• ■■..■■■■ ¥.■ . > 



,: *-£ "..-.;-'J§SE»^i^; 



^^55* 



-A. WEST EDGE OF LINDA VISTA MESA NEAR ENCINITAS. 
Shows sea cliff. Looking north. 







^y 




5. BEACH PEBBLES DEPOSITED BY STRANDED SEAWEED, ENCINITAS. 



PHYSIOGRAPHY. 23 

sand and gravel down their valleys and filling the lagoons hehind 
the bars. In this manner a nearly continuous terrace was formed 
along the shore beneath the water's edge. When the land was again 
elevated the newly formed terrace emerged, the streams began to 
remove the filling from their valleys, and the bars were cut through. 
As the terrace rose new streams were established on it and produced 
topographic features that are distinctly contrasted to those adjacent 
on the east. This relation is called by Salisbury a " topographic 
unconformity." 1 The land had probably reached an elevation some- 
what higher than it is at present and the streams had probably cut 
their beds slightly lower than they now are when sinking began 
again. This sinking, possibly now in progress, is shown by the partly 
drowned and consequently marshy valleys of all streams that reach 
the ocean in this part of the county. 

About 3 miles north of La Jolla a dike of igneous rock (basalt) 
about 2 feet wide extends from the base of the cliffs southwestward 
into the ocean (see PI. Ill, in pocket, and PL IV, A). The total 
length of the dike exposed at low water is, according to Fairbanks, 
about 1,800 feet. Its northern end is now covered by talus, so that 
its relation to the mesa formations is concealed, but in 1892 Fair- 
banks reported that it did not extend into the cliffs, "the only signs 
being a fault in line with the dike." 2 

At many places along the shore, but particularly between Delmar 
and Encinitas, accumulations of large flattened, smooth-surfaced 
pebbles or small boulders lie a few feet above high-water mark and 
extend along the beach in narrow ridges, in some places 2 J feet in 
height. The average pebble is about 5 inches long, 3 inches wide, 
and 2 inches thick. Plate V, B, shows one of these ridges near 
Encinitas. The concentration of pebbles in this form is due to the 
action of storm waves whose inrush carries sand and pebbles to a 
position beyond the reach of the waves under normal conditions. 
These waves retreat much more feebly than they advance, and con- 
sequently while the sand and small pebbles are dragged back to the 
surf, the large pebbles are left stranded. It has been observed that 
kelp, which is brought ashore by the waves, sometimes carries pebbles 
of this kind inclosed in its rootlike bases. These pebbles have served 
as supports or anchors for the kelp and have been lifted from the 
sea bottom when the plant attained a sufficient buoyancy, or have 
been dragged along when the plants were torn from their moorings 
by storm waves. 3 Fragments of seaweeds, some of which are root- 

1 Salisbury, R. D., Three new physiographic terms: Jour. Geology, vol. 12, 1904. Salisbury, R. D., and 
Atwood, W. W., The interpretation of topographic maps: U. S. Geol. Survey Prof. Paper 60, p. 73, pi. 151 f 
1909. 

* Fairbanks, H". W., Geology of San Diego County, etc.: California State Min. Bur. Eleventh Ann. 
Rept., p. 97, 1892. 

8 Shaler, N. S., Sea and Land, p. 55, 1894. 



24 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

like masses still inclosing pebbles, are shown in Plate V, B. Atten- 
tion is being directed to these deposits as a possible source of grinding 
pebbles. 

From La Jolla southward to the international boundary the coast 
line is characterized by peninsulas, bays, steep wave-washed cliffs, 
sandy beaches, and muddy and marshy tidal flats. The peninsula 
on which La Jolla stands is the most noteworthy irregularity of the 
coast. It extends about 2 miles into the sea and is about 4 miles 
wide. Soledad Mountain, which forms this peninsula, is 822 feet 
high and is separated from the bench on the east by Rose Canyon, 
which has cut down 300 to 400 feet below the level of the mesa. A 
record of the oscillations of the coast line is preserved on Soledad 
Mountain in sea terraces which appear at short vertical intervals 
from the base to the top of the mountain. For a distance of several 
miles along the shore near La Jolla the present sea cliffs are washed 
by the waves at high tide, and in some places they have been deeply 
carved by wave action. Just east of La Jolla, at the edge of the 
village, the waves have cut large caves which, though flooded at 
high tide, may be entered at low tide (see PL IV, B) and which are 
objects of much interest to sight-seers. 

Soledad Mountain may owe its origin to a fault that extends 
southeasterly along its eastern flank approximately in line with Rose 
Canyon. 

Point Loma forms a second peninsula probably produced in the 
same way as Soledad Mountain, but its greatest elevation, which is 
at the southern end of the point, is only 400 feet. This peninsula is 
7 miles long, north and south, and varies in width from a quarter of 
a mile on the south to 3 miles on the north. The neck of land that 
connects Point Loma with the mainland consists of delta deposits 
laid down by San Diego River. Point Loma was an island during 
Quaternary time and it is said that it continued an island to a time 
within the memory of Indians living when San Diego was settled. 

Mission Bay occupies a syncline of which Soledad Mountain forms 
the northern and Point Loma the southern limb. The silting up 
of this bay has reached a fairly advanced stage. The entrance is 
nearly closed by Point Medanos, which is a sand bar extending 
southward from the north shore to within a quarter of a mile of the 
south shore, and owing to its continuation under water the depth of 
water in the present channel at mean low tide is only 4 feet. Over 
fully 75 per cent of the area of the bay soundings have shown a depth 
at low water of less than 2 feet, and depths greater than 20 feet were 
measured at only two places. A mud flat that covers about 2 square 
miles and lies only slightly above high water forms the southern 
shore of the bay. 



PHYSIOGRAPHY. 25 

From Point Loma south to the Mexican boundary the coastal belt 
is occupied by San Diego Bay and the lowlands, including a consider- 
able area of tidal marsh between the mouth of Otay River and the 
south slope of Tia Juana Valley. The topographic features of this 
area and depths of water in the bay and off its entrance are shown 
on Plate VI. San Diego River formerly emptied into San Diego 
Bay, but the silt which it carried into the bay threatened to destroy 
the harbor so that in 1853 the stream was diverted into Mission Bay. 1 
The rate of silting up of the bay was thus materially reduced but the 
amount of sediment carried in by other streams necessitates dredging 
to keep the bay open for shipping. 

The long neck of land that connects Coronado Island with the main- 
land and incloses the bay on the east is a sand bar built by waves 
and shore currents that have also formed a narrow land connection 
between Coronado Island and North Island and would undoubtedly 
close the channel between North Island and Point Loma but for the 
jetty east of the channel, which was constructed to prevent the 
closing of the bay. 

Fairbanks 2 states that "San Diego Bay has probably been formed 
through the drowning of a river valley in connection with the action 
of ocean waves and currents." It is possible that when the land 
stood at a higher level Tia Juana River may have flowed through 
that valley, Otay and Sweetwater rivers being then tributary to it. 
The Tia Juana seems to be much more competent to occupy such a 
valley than the Otay, although no evidence has been found as yet 
that a river crossed the terraces between Tia Juana River and San 
Diego Bay. - It is likely that a stream as large as the Tia Juana 
would leave recognizable traces of an ancient channel. 

• 

TERRACES. 
GENERAL RELATIONS. 

The terraces, locally known as mesas, range in height from 20 to 
1,200 feet above sea level, but they are most extensively developed 
between elevations of 300 and 500 feet. North of Otay River the 
principal terraces slope gently toward the ocean from an elevation of 
about 500 feet near the eastern margin to about 300 feet near the west- 
ern margin. South of Otay River the terrace, or top of the mesa, slopes 
in the opposite direction. The western edge of Otay Mesa (see PL 
VI) is nearly 550 feet high; 4 miles farther east the elevation is but 
little more than 500 feet. The actual slope is, however, much less 
than it appears to be when the terrace is viewed from a lower level 
a few miles north of its northern edge. 

i U. S. Army Chief of Engineers, Ann. Rept. for 1868, p. 886. 

2 Fairbanks, H. W., The physiography of California, p. 43; reprinted from Am. Bureau Geog. Bull., vol. 
2, pp. 232-252, 329-350, 1901. 



26 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

The terraces were originally formed below sea level. Each in turn 
was leveled by the combined wave erosion and marine deposition, 
as described on page 22, and then lifted above the sea and subjected 
to stream erosion. The highest terrace is the oldest. Most of the 
present irregularities of the surface are due to stream action. The 
elevation of the land progressed irregularly, being relatively rapid at 
some times and much slower at others. During times of slow or 
interrupted rise the sea cut cliffs at successively lower levels on the 
edges of the terraces, such as those now being formed along the 
shore at La Jolla, and during times of rapid elevation parts of the 
sea bottom were lifted above the waves to form successive terraces. 
These cliffs and terraces are now conspicuous features of the 
landscape. 

In the region about San Diego Bay, as shown by Plate VI (in pocket), 
there are five terraces, which, north of Tia Juana River, are, respec- 
tively, about 20, 50, 100, 250, and 500 feet above sea level. These 
elevations are, however, only general, for each of the terraces was 
originally somewhat uneven, and, moreover, they have been con- 
siderably modified by erosion, so that their true relations can be seen 
only by observation from selected localities. Viewed from a dis- 
tance, as from a point northeast of Chulavista on the south bluff of 
Sweetwater Valley, the minor irregularities of the terraces disappear, 
and they are seen as a succession of nearly flat benches or steps rising 
from the low shore of San Diego Bay to the border of the highlands 
on the east. 

The darker colors on Plate VI indicate the remnants of the ter- 
races; the lighter shades indicate their probable extent previous to 
erosion. As indicated on this map the marine terraces extend into 
the major valleys and show that these valleys were estuaries when 
the terraces were formed. 

The terraces south of Tia Juana River exhibit somewhat different 
topographic relations. Only a small part of these terraces is in the 
United States, but even in this part the cliffs are steeper and higher, 
and the terraces are separated by larger vertical intervals than the 
corresponding cliffs and terraces north of the river. For example, 
the terrace on which Oneonta is situated, which is the highest terrace 
between Tia Juana and Otay rivers on which Quaternary fossils are 
found, is about 50 feet above sea level; but the broad, perfectly de- 
veloped terrace which extends for many miles south of the Tia Juana 
and on which Quaternary fossils are abundant, is about 100 feet above 
sea level along its eastern margin and is nowhere less than 75 feet above 
the sea. The terrace north of Tia Juana River which, at an elevation 
of about 200 feet, corresponds to a terrace south of the Tia Juana at 
an elevation of about 400 feet, and Otay Mesa, shown on Plate VI at 
about 500 feet above sea level, is represented south of the Tia Juana 



PHYSIOGRAPHY. 27 

by a table-land that is about 700 feet above sea level and that extends 
from a point near the international boundary southward to Table 
Mountain. Each of these terraces is of marine origin, and therefore 
must have been of uniform elevation throughout its extent when it 
was formed. If the correlations of the disconnected parts of the 
several terraces as indicated are correct, their present relations prob- 
ably mean that the land south of Tia Juana River has risen higher 
and more rapidly than that to the north. 

In addition to the principal terraces shown on Plate VI, compara- 
tively inconspicuous benches at other elevations mark short pauses 
in the retreat of the shore line. One of these is on the south side of 
Otay Mesa at 425 feet above sea level, and another, at 300 feet above 
sea level, may be seen at several places between the international 
boundary and Sweetwater River. No doubt careful field studies 
would reveal still others. 

In the geologic reports of the United States and Mexican Boundary 
Survey, Parry 1 mentions three terraces in this region, the lowest 
being that which is shown on Plate VI (in pocket) as the Nestor 
plain, the second being the top of Otay Mesa, and the third Table 
Mountain, a flat-topped mountain about 17 miles south of the inter- 
national boundary, visible from San Diego as a conspicuous feature 
on the sky line. Surveys made in 1909 show the altitude of Table 
Mountain to be 2,275 feet above sea level. 2 It is not necessary, how- 
ever, to go south of the boundary to find remnants of a much higher 
terrace than Otay Mesa. The high ridges that radiate from the gran- 
ite range west of Foster and extend westward to Miramar and from 
El Cajon Valley to Poway Valley and that form those steep grades 
in the county highway known as the " Poway grade" are remnants 
of a very old and much eroded marine delta terrace. The tops of 
these ridges are about 900 feet above sea level near the west 
ends and rise gradually to about 1,200 feet above sea level at the 
east, where they join the higher slopes of crystalline rocks. These 
branching ridges taken together are referred to in this report as 
Poway Mesa. Linda Vista Mesa extends from the western edge of 
Poway Mesa to Soledad Mountain and the ocean and was originally 
continuous southward to Otay Mesa. Comparison of the amounts 
of erosion that have been accomplished on the surfaces of Linda 
Vista Mesa and Poway Mesa gives some indication of the relative 
ages of the two original terraces. The map forming Plate VII shows 
parts of Linda Vista Mesa and Poway Mesa. As shown on this map, 
Linda Vista Mesa is in general flat and stands 400 to 500 feet above 
sea level between the ocean and Miramar. Its western part is dis- 

1 Parry, C. C, and Schott, Arthur, Geological reports: United States and Mexican Boundary Survey, 
Vol. 1, pt. 2, chap. 5, p. 86, 1857. 

2 U. S. Hydrographic Office, Navy Mariners' Chart No. 1149, "San Quentin to San Diego," 1909. 



28 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

sected by narrow canyons that are separated by broad, flat divides, 
but its eastern part is a broad gently sloping plain that is practically 
untouched by erosion. Farther south the terrace of which this was 
originally a part is cut through by th#,d^ep broad valleys of San 
Diego, Sweetwater, and Otay rivers, and the several parts between 
these main streams are much dissected by smaller valleys and ravines. 
Yet even here considerable tracts of the original nearly flat terrace 
are still preserved. These topographic features are distinctly in con- 
trast to" those of the Poway Mesa, a part of which east of Miramar 
is shown in Plate VII. The canyons of the Poway Mesa are so close 
together that none of the original flat top remains, the crests of the 
ridges being narrow and in many places less than 10 feet wide. These 
divides, however, have probably not been cut far below the level of 
the original terrace. They are nearly uniform in height, sloping from 
about 1,200 feet above sea level on the east to about 900 feet on the 
west and they represent fairly well the slope of the terrace when 
erosion began. The topography of Linda Vista Mesa is " young," 
that of Poway Mesa is "mature," showing that the higher terrace 
has been exposed to erosion a much longer time tjian the lower one. 

POWAY MESA. 

The original extent of Poway Mesa can not be determined. Rem- 
nants of it are preserved west and southwest of El Cajon Valley and 
north of Poway Valley. At the time of the earth movement which 
brought Linda Vista Mesa above seal level Poway Mesa probably 
extended southward to the vicinity of La Mesa, westward over the 
site of Miramar, and northward nearly to Black Mountain. Pre- 
vious to that time it may have extended much farther westward. 

Considerable interest attaches to this high terrace on account of 
its possible relation to ancient stream gravel that extends eastward 
as far as Witch Creek, as shown on Plate III. This gravel now caps 
mountains which rise to elevations of 2,000 to 3,500 feet and it has 
generally been regarded as marking the course of some large ancient 
river. As suggested by Fairbanks (see p. 41), and as shown on the 
map (PI. Ill), Poway Mesa may be the delta of such a river. But 
the region has been lifted 1,500 feet or more since the Poway Mesa 
was formed, and probably most of the features of the highland have 
since been developed, so that it is now impossible to visualize accu- 
rately the physiography of that time. An explanation of the origin 
of the so-called " placer gravels" which has been brought to the 
attention of many residents of San Diego is that Colorado River once 
may have crossed the country along the line of gravel deposits and, 
flowing across the terraces and through the present site of San Diego, 
entered San Diego Bay, and that the gravels, together with supposed 
stream deposits on the terrace (and underlying San Diego), were laid 




ANGLE 

y Terrac 



U S. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 440 PLATE VD 



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TOPOGRAPHIC MAP OF A PART OF LA JOLLA QUADRANGLE, CALIFORNIA 

Showing erosional features of Lindavista and Poway Terraces 

Scale agsim 



Contour interval 25 ieet. 
Datum is mean sea-Utvi. 



PHYSIOGRAPHY. 29 

down by this river. But it should be remembered that when Poway 
Mesa was being built the present site of San Diego was possibly 
several hundred feet below sea level, and that the shore line must 
have been at least as far east as Foster, so that no fluviatile deposits 
in or near San Diego could reasonably be attributed to the same 
origin as the stream gravels east of Foster. The origin of the stream 
which deposited the gravels is altogether a matter of conjecture, but 
it certainly had no relation to present topographic conditions. 

MOUNDS. 

The surface of Linda Vista Mesa and, to a less extent, the terraces 
north and south of it are dotted with thousands of low, round 
hummocks that range in height from a few inches to 3 feet and in 
diameter from about 3 feet to 15 feet. Over wide areas they are 
found very close together, some being separated by less than 3 feet 
(PI. VIII). Some casual observers have supposed them to have been 
formed by gas escaping from the freshly deposited material ; others 
believe them to represent the work of springs of water while the plain 
was still near sea level. They are, however, no doubt correctly 
ascribed to the action of the wind as it sweeps through the sparse 
desert vegetation and blows away the loose soil except where it is 
held by plant roots. One or two shrubs are generally found growing 
in the center of each hummock, though many of them are bare. 
The barren hummocks merely indicate a former distribution of vege- 
tation. These products of wind erosion are common features of arid 
plains in western North America, 1 where, owing to the absence of 
wind breakers and the sparse soil the eroding power of prevailing 
strong winds is particularly effective. A report of the United States 
Weather Bureau 2 describes the eroding and transporting power of 
the winds : 

The winds throughout the entire section are light, except when northern storms 
move southward, or when Sonora storms in the summer months move slowly north- 
westward and recurve. There are certain well-marked winds, known as Santa Ana 
or desert winds, which blow for periods of about three days from the north. These 
winds are generally dust-laden, are very dry, and are extremely trying to human 
and animal life. In San Diego County these are known as desert winds, as they blow 
rom the east; but in the other counties the direction is more from the north. Mr. 
Campbell describes these winds as follows, in the Monthly Weather Review for 
October, 1906: 

"They blow during periods of 3 to 6 or 9 days; but rarely last beyond 21 days. 
They are cool winds to us here on the mountains, while on the coast they are hot, 
and are skin-drying, lip-cracking, unpleasant visitants. After they reach the coast 
the force is mostly out of them. Sometimes their force at Campo rivals a hurricane. 

i See Chamberlin, T. C, and Salisbury, R. D., Geology, vol. 1, p. 22, 1904. See also Barnes, G. W., The 
Hillocks or mound formations of San Diego, Calif.: Am. Naturalist, vol. 13, p. 565; 1879. Wallace, Alfred 
R., Glacial drift of California: Nature, vol. 15, p. 274, Jan. 25, 1877. Le Conte, Joseph, Hog wallows or 
prairie mounds: Nature, vol. 15, p. 530, Apr. 19, 1877. 

8 MsAdie, Alsxander, Summaries of climatological data, by sections: U. S. Weather Bureau Bull. W, 
vol. 1, sec. 13, p. 2, 1912. 



30 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



1 



In places they pierce window panes with little round holes as if drilled by the 
coarse gravel they carry like a dose of small shot. On my ranch on the Laguna 
Mountains, at an elevation of 6,500 feet, all the east side is in big pine and oak timber 
for some miles; yet on the last ridge overlooking the desert on the east, not a tree 
grows for miles, although north and south they grow up to within 200 yards of it all 
along. Even the brush changes on that last ridge from a growth of 6 to 10 feet down 
to all dwarf, creeping and clinging close to the ground, but of the same variety as 
the upright. These winds are so violent that they often tear down houses. Their 
duration is from October to March. We generally get our first fall rains after the 
blow is over; but this year the first rain, on the 15th, preceded this one. If they come 
in the spring after the first blooms form, both the blooms and the young fruit drop 
off the trees after a short time. The barometer responds more quickly to an east 
wind than to any other change of weather." 

ANCIENT BEACH RIDGES. 

An interesting topographic feature on Linda Vista Mesa is a series 
of low ridges that extend from Mission Valley northward for 6 to 
15 miles, in many places being brought into exaggerated relief by 
erosion. Most of these ridges are capped by a brigh-tred sandstone 
which is indicated on the geologic map (PI. Ill, in pocket). Por- 
tions of three of these ridges, somewhat dissected by transverse 
canyons but still easily identified are shown on Plate VII. The 
letter "A" marks the northern extremity of a. ridge that extends 
south to Mission Valley; the letter "B" marks disconnected parts 
of a ridge that also extends to Mission Valley. The ridge marked 
"C" extends only short distances north and south of the edges of 
the area shown on Plate VII. It is believed that these ridges were 
formed by the waves along former shore lines just as similar ridges 
are now being formed along the shore near the international boundary, 
or in a manner very similar to that in which the sand spit that 
extends from Coronado south to the mainland (see p. 25) was 
recently formed. If the land were raised 100 feet San Diego Bay 
would be entirely dry, and the sand spit would form a ridge which 
would have very much the appearance of the old ridges on Linda 
Vista Mesa. A more striking example of the origin of these ridges 
may be seen in the much more recently formed sand ridge which 
extends along the shore between the railroad and the edge of the 
bluffs from Delmar nearly to Oceanside and which for long dis- 
tances cuts off the view of the ocean from the train. This ridge 
rests on the extreme edge of the mesa, as much as 100 feet above 
sea* level in many places, but it has been much more recently 
elevated above the sea (see p. 69) than the higher ridges farther 
east. 

SAN ONOFRE HILLS. 

North of San Luis Rey River the broad terraces and widely 
separated canyons, characteristic of the mesa farther south, give way 
to high, rounded steep sloped hills separated by deep, narrow, inter- 



PHYSIOGRAPHY. 31 

locking valleys. The hills reach elevations ranging from 500 to 600 
feet above sea level and have an average height of about 300 feet. 
Beginning about 3 miles north of Ysidora and extending northwest 
to Arroyo San Mateo the San Onofre Hills (including San Onofre 
Mountain) rise to elevations of 800 to 1,735 feet, and are flanked on 
the east by the dissected terrace, 300 to 500 feet high, which corre- 
sponds to Linda Vista Mesa and on the west by a low narrow sloping 
plain bordering the coast. The San Onofre Hills are about 3 miles 
wide and are intersected by several canyons which cut below the 
level of the terrace on the east. These hills are believed to have been 
formed later than the terraces and probably owe their origin to an 
upward movement of the land between the ocean and a fault that 
extends along their eastern base. 

MAJOR VALLEYS. 

The valleys referred to in this report as major valleys are those 
occupied by Santa Margarita, San Luis Key, San Dieguito, San 
Diego, Sweetwater, Otay, and Tia Juana rivers. They are charac- 
terized by wide flat gently sloping floors, bordered by very steep 
slopes or bluffs several hundred feet high, and they contain streams 
that rise far back in the highland area. 

Santa Margarita Valley. — Halfway between Deluz station and 
Home ranch Santa Margarita River leaves a rock gorge and enters 
a broad valley. As far downstream as the Home ranch this valley 
is bordered on the west by granite hills and on the east by bluffs that 
lead up to a terrace or mesa about 300 feet ' above the valley floor. 
Below the Home ranch it is bordered on both sides by bluffs that 
lead up the terrace. The valley is constricted at the Home ranch and 
near Ysidora, but its average width is nearly a half mile. The river 
is about 100 feet above sea level one mile north of the Home ranch, 
and its gradient is about 10 feet per mile from this point to the ocean- 

San Luis Rey Valley .—About 3 miles east of the San Luis Rey 
Mission San Luis Rey River leaves its gorge in the highland area and 
enters a flat-bottomed valley incised about 300 feet below the terraces. 
At this point, approximately 8 miles from the ocean, the river is at 
an elevation of about 90 feet above sea level. Its grade below this 
point is about 11 feet to the mile. East of the mission the valley is 
about 2 miles wide but farther downstream it becomes gradually 
narrower, and near Oceanside it is hardly a tenth of a mile in width. 

San Dieguito Valley.— San Dieguito River leaves its rock gorge about 

6 miles from the ocean and enters a valley which opens abruptly to a 
width of half a mile. At the mouth of the gorge the river is about 
40 feet above sea level and thence to its mouth its gradient is about 

7 feet per mile. Through the entire length of the valley the walls 
rise precipitously 100 to 300 feet above the valley floor. 



32 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Mission Valley. — Mission Valley, which is the valley of San Diego 
River, extends from the rock gorge west of Cowles Mountain south- 
westward to Mission Bay, a distance of 8 miles. From the mouth of 
the gorge to the old San Diego Mission the valley is about a third of a 
mile wide, and from the Old Mission to Old Town, a distance of 6 
miles, it has a fairly uniform width of about three-fifths of a mile. 
The valley floor is flat throughout its entire length, and from its 
head to the vicinity of Old Town is bordered on both sides by precipi- 
tous cliffs that rise 100 to 300 feet to the levels of the terraces. At 
Old Town the terraces come to an end and the valley forms part of 
the narrow coastal belt. The elevation of the river at the mouth of 
the gorge is 100 feet above sea level, and the slope from this point 
to the bay is about 1 1 feet to the mile. 

Sweetwater Valley. — Sweetwater Valley extends from the vicinity 
of Aloha, where it leaves the highland area, to San Diego Bay, a 
distance of 8 miles. In this distance the descent is 100 feet, or 12J 
feet per mile. This valley, like Mission Valley, has a flat bottom and 
steep sides leading up to the terraces 100 to 300 feet above the valley 
levels. It is, however, narrower than Mission Valley, being only 
one-fourth to one-half mile wide. It follows a meandering course, 
and in this respect is distinctly in contrast to the lower parts of the 
other major valleys, all of which are more nearly straight. 

Otay Valley. — Otay Valley extends due west from the base of 
Otay Mountain to the south end of San Diego Bay. Its sides are 
high bluffs as far west as the village of Otay, but thence to the bay 
the stream flows across a low plain. Otay Valley differs from the 
other major valleys in that its grade is much steeper in the lower — 
miles, about 25 feet to the mile, and, in that the valley floor, instead 
of being flat, slopes rather steeply from the base of the bluffs on each 
side to the stream channel, which through most of its length is in the 
middle of the valley. The significance of these features is discussed 
on page 33. 

Tia J nana Valley. — Tia Juana River crosses to the north side of 
the international boundary at Tia Juana (PL II, in pocket) and ex- 
tends westward 6 miles to the ocean. The valley floor at the bound- 
ary is about a mile wide and is bordered on the south by cliffs that 
rise 400 feet above the river. On the north side of the valley the 
bluffs, which extend northwestward toward Nestor and are more 
than 400 feet high at Tia Juana, rapidly diminish in height and 
leave a broad, plain through which the stream flows westward 
between low sloping banks less than 25 feet high. The river is about 
50 feet above sea level at Tia Juana, Calif., and slopes westward at 
the rate of 8 feet to the mile. 

Origin of major valleys. — The features of the major valleys in this 
region are due 'in part to the nature of the streams and in part to the 














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PHYSIOGRAPHY. 33 

alternate rising and sinking of the land. The major streams originate 
in the mountains and their headwaters drain large areas. The 
precipitation is so great at certain times that large volumes of 
water sweep through the valleys, but during long intervals the amount 
of water collected in the highlands is so much smaller that it sinks 
into the sands of the river beds as soon as it reaches the eastern 
edge of the coastal belt. Broad streamways which intermittently 
discharge large volumes of water are characteristic of streams in arid 
regions, and this feature of the major valleys in San Diego County 
is due in part to the action of flood waters. Unusually heavy floods 
which swept the valleys of this area in January, 1916, furnished a 
wealth of evidence as to the process and efficiency of flood erosion. 
The accompanying photographs taken before and after the flood of 
January, 1916, Plates IX, X, and- XI, show results of flood erosion. 
But the form of these valleys is in part due also to the fact that during a 
recent period in the geologic history of the region the land stood 
higher than at present, and the major streams were able to cut their 
valleys down to a level which is now 100 to 200 feet below the level 
of the sea, as is shown by the logs of wells sunk in the valleys.. (See 
p. 1 1 1) . The streams have therefore partly filled their old valleys and 
the widths of the present valley floors represent the distance between 
the valley walls possibly as much as 200 feet above their original 
bases. That the sides of the valleys are generally very steep, and 
in places nearly vertical, is due to the general aridity of the region. 
The flood waters are efficient in removing talus material which falls 
or slides down to the foot of the bluffs, but the tops of the bluffs 
are not worn back as rapidly as in regions where the rains are more 
frequent and the run-off on the surface is relatively larger. The 
rainfall on the terraces is small and is rapidly disposed of by the 
minor streams and by evaporation and percolation, so that, as in all 
arid regions, higher and lower levels are separated by sharp breaks 
and very steep slopes. 

As mentioned on page 32, Otay Valley has a much steeper grade 
than the other major valleys and its floor, instead of being flat, slopes 
from the sides toward the stream channel. Moreover, records of 
wells show that the filling in this valley is comparatively shallow. 
These conditions indicate that Otay River, probably because it was 
younger and smaller, was unable to erode its valley to the same depth 
as the other major streams during the time when the land stood higher; 
consequently when the subsequent lowering of the land carried the 
bottoms of all the other major valley floors well below sea level only 
a part of Otay Valley was submerged and that to a comparatively 
shallow depth. Otay Valley therefore has characteristics of both the 
major and the minor valleys. 
115536°— 19— wsp 446 3 



34 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



& 



/ 



The lower parts of all the major valleys and some of the minor 
valleys are marshy, and some of the streams are completely cut off 
from the ocean by beach ridges. These features are discussed with 
other coast-line features (p. 22). 

MINOR VALLEYS. 

The largest of the minor valleys are those occupied by San Mateo, 
Loma Alta, Buena Vista, Agua Hedionda, San Marcos, Escondido, 

McGonigle, Los Penasqui- 
f* ^ tos, Soledad, Rose, and Las 

\\*\ Choyas creeks/ Los Pe- 

\\ nasquitos Creek joins Sole- 

ly , dad Creek 4 miles from the 

ocean, but all the other 
creeks mentioned discharge 
either directly into the 
ocean or into Mission or 
San Diego bays. Most of 
the minor valleys, however, 
are tributary to the major 
valleys. Except Escondido 
Creek and Los Penasquitos 
Creek, both of which rise to 
the highland area, the minor 
streams are confined to the 
coastal region. In general 
they occupy steep-floored 
valleys, the distance from 
the top of the terrace to the 
floors of the major valleys 
being usually short, and, 
except at the mouths of 
those that discharge into the ocean, they are without flood plains. 
Some of the. minor valleys cut in Linda Vista Mesa follow peculiar 
angular courses, as illustrated by the Tecolote drainage system, shown 
in figure 1. This condition is due to the control of the drainage by 
the ancient beach ridges. The surface water, which would normally 
flow westward in the direction of the general slope of the terrace, was 
deflected to the north and to the south by the ridges until it was able 
to cut across them at right angles. Once established, the streams 
deepened their valleys in these places. 

THE HIGHLAND AREA. 
GENERAL FEATURES. 

The highland area lies east of the coastal belt and extends from 
the highest terraces and beyond the eastern boundary of the area 




Figure 1.— The Tecolote drainage system, showing the an- 
gular courses of minor streams produced by ancient beach 
ridges on Linda Vista Mesa. 



PHYSIOGKAPHY. 35 

covered by this report. For the purpose of obtaining a general view 
of the region, W. A. Goodyear in 1872 ascended Cuyamaca Mountain, 
which rises to an elevation of 6,515 feet above sea level, in the eastern 
part of the area. The following graphic description is quoted from 
his report. 1 

The view from the summit of this peak is very extensive, reaching toward the south 
far into the Republic of Mexico and toward the north as far as the San Jacinto Peak and 
Mount San Bernardino, while to the west and southwest the shore for many miles, 
together with a very broad expanse of the ocean, are in sight; and to the northeast a 
considerable part of the Coahuilla Valley or the northwestern part of the Colorado 
Desert, and beyond it a long stretch of the southeastern continuation of the San Ber- 
nardino range of mountains running to the Colorado River along the northeast side 
of the Desert Valley, can also be seen. This is the best point from which to obtain a 
bird's-eye view of the general form and character of the mountains in the western 
part of San Diego County. 

Looking down from this standpoint over the surrounding region, the whole country 
from just back of San Diego easterly to the western edge of the desert is like an angry 
ocean of knobby peaks more or less isolated, with short ridges running in every pos- 
sible direction and inclosing between and amongst them numerous small and irregular 
valleys. As a general rule, the higher peaks and ridges rise from 1,000 to 2,500 feet 
above the little valleys and canyons around their immediate bases. But in going 
easterly from the coas,t each successive little valley is higher than the one immediately 
preceding it, and the dominant peaks and ridges are also gradually higher and higher 
above the sea until we reach the irregular line of the main summit crest or water divide 
of the range, when the mountains break suddenly off and fall within a very few miles 
from 4,000 to 5,000 feet or more with an abrupt and precipitous front toward the east 
to the western edge of the desert. 

Together with the coastal belt, the highland area has been repeat- 
edly raised and lowered with respect to the sea level, but so far as is 
known these oscillations have not carried this highland area below 
sea level since an early geologic time. During all the time that the 
upper formations underlying the coastal belt were being laid down, 
and while the terraces were being formed and dissected, the high- 
land area stood above the sea and was undergoing erosion. The 
movements of the land surface with respect to sea level produced 
results in the coastal belt that are readily recognized in the structure 
and topography. But in the highland area the effects were princi- 
pally manifested in changing the gradients of the streams and, to 
some extent, in faulting and folding the rocks. In an area of crys- 
talline rooks such as this neither the particular results of the several 
movements nor the chronologic order of their occurrence are readily 
detected. For this reason the physiographic history of the highland 
area is much more obscure than that of the coastal belt. However, 
a general conception of the origin and growth of the mountains and 
stream valleys may be obtained from a study of their individual 
characteristics and their interrelations. 

1 Goodyear, W. A., San Diego County: California State Min. Bur. Eighth Ann. Rept., 1887-88, p. 520. 



36 GEOUND WATERS OF WESTERN" SAN DIEGO COUNTY, CALIF. 

THE MOUNTAINS. 
GENERAL RELATIONS. 

The mountains of the highland area belong to what has been called 
the Peninsular Range. As stated by Fairbanks/ this range extends 
southward, " forming the backbone of the peninsula of Lower Cali- 
fornia. Northward it becomes broader and more complex, rising in 
the lofty San Jacinto and San Bernardino ranges on the east, and 
the Santa Ana Range on the west, while the region between is filled 
with mountains and valleys irregularly disposed." 

It will be seen from the map (PL II, in pocket) that in the area 
discussed in this report there is little regularity in the distribution 
of mountain peaks—that they do not lie in distinct ranges. Eleva- 
tions of about 6,000 feet are common in the northeastern part, the 
principal peaks being Morgan Hill (elevation 5,628 feet), Palomar 
Mountain (6,126 feet), Hot Springs Mountain (6,250 feet), North Peak 
(6,028 feet), Middle Peak (5,750 feet), and Cuyamaca Peak (6,515 
feet). The general elevation of the eastern half of the area is more 
than 3,000 feet above sea level; that of the western half ranges from 
500 to 1,500 feet above sea level, though a few peaks, such as Otay 
Mountain (elevation 3,572 feet), San Miguel Mountain (2,573 feet) 
ElCajon Mountain (3,680 feet), and Woodson Mountain (2,890 feet), 
exceed 2,500 feet. 

The southern slopes of the mountains are commonly nearly barren 
of vegetation, but most of the northern slopes are covered by chapar- 
ral and scattered groves of isolated trees of cedar, oak, live oak, pines, 
and firs. Excellent grazing is found on many of the mountain slopes 
and in nearly all the valleys. 

Notwithstanding the complexity of the surface features, as seen 
from an elevated position or as shown by the topographic map, a 
number of features afford a certain degree of uniformity. The divide 
between the ocean drainage on the west and the gulf drainage on the 
east trends northwesterly, a direction roughly parallel to the shore 
line. The same general direction is followed by numerous dikes 
throughout the highland area, by a scarplike range of low hills at the 
eastern edge of Poway Mesa, by the range composed of porphyritic 
rocks (including Otay Mountains, San Miguel Mountain, and Cowles 
Mountain) and by the San Onofre Hills. Close field observation 
reveals among the smaller features a considerable degree of parallel- 
ism to this direction that is entirely masked by the larger topo- 
graphic forms shown on the map. 

ORIGIN. 

In general the mountains of this area have been regarded as due 
principally to erosion. It is believed that previous to the elevation 

i Fairbanks, H. W., The physiography of California, reprinted from Am. Bur. Geog. Bull., vol. 2, pp. 
232-252, 329-350, 1901. 



PHYSIOGRAPHY. 37 

of the land it was a peneplain — that is, a region reduced by stream 
erosion until it had comparatively little relief — and that as the land 
was raised the streams were rejuvenated and cut their valleys to their 
present depths. Evidence of the former existence of a peneplain is 
found on the tops of many of the mountains throughout the area. 
Fairbanks * describes this evidence as follows: 

The features of an ancient base level are particularly noticeable upon the crests 
of the mountains and ridges. The summit of Smiths Mountain as well as that of the 
Laguna Mountains are fine examples of flat topped. Viewed from a point east of 
Fallbrook, the western slope of the mountains forms a nearly even sky line gently 
dipping toward the coast. The present canyons have been eroded in this ancient 
plain and in many cases they have widened to extensive valleys. The main streams 
are completely graded, flowing over a sand floor. 

Stream erosion has probably been the principal direct agent in 
producing this topography, and erosion is notably affected by rising 
or lowering of the land surface. Such movements are also frequently 
accompanied by a certain amount of faulting. Some of the topo- 
graphic features are due primarily to faulting. Smiths Mountain and 
the range of peaks forming the divide owe their origin to faulting, as 
explained by Fairbanks 2 and as indicated by the California Earth- 
quake Commission. Three faults, presumably of considerable 
magnitude, one on each side of Smiths Mountain and Warners Valley 
and one along the east side of the San Onofre hills, are shown on the 
map published by the California Earthquake Commission (see PI. Ill) 
and small faults, showing displacement of a few feet, are numerous 
throughout the area. Plate XII shows a small fault encountered in 
the Himalaya mine, near Mesa Grande. In an area of crystalline 
rocks, however, it is exceedingly difficult and often impossible to 
detect faults which are too large to be identified by the displacement 
of minor structures, such as joints and veins, and which, though of 
sufficient magnitude to modify the topography, are still too small to 
show the zones of shearing and crushing characteristic of great faults. 
In such an area therefore many faults of moderate size are traceable 
only by topographic evidence, and as that kind of evidence is rarely 
conclusive, knowledge of the extent to which faulting of this character 
has been effective is necessarily indefinite. The geologic history and 
the structure of the region make it reasonable to suppose that faulting 
has contributed toward the development of the present topography 
of the highland area in two ways — first, directly, by lifting certain 
blocks of the earth's crust higher than others and so forming moun- 
tains; and, second, indirectedly, by fracturing the rocks so that in 
places they were more easily worn away by the streams (see p. 49), 
and valleys were formed. 

i Fairbanks, H. W., The physiography of California: Am. Bur. Geog. Bull., vol. 2, pp. 232-252, 329-350, 
1901. 

2 Idem, p. 350. See also Report of California State Earthquake Commission, Andrew C. Lawson, 
chairman, 1910, Atlas, Map No. 1. 



38 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

THE RIVER VALLEYS. 

The principal streams of the highland area rise near the divide and 
flow to the ocean. Except where they cross the valley plains they 
occupy deep narrow gorges whose walls are of rock but whose floors 
are very commonly of sand. Well borings have shown that the rock 
bottoms underlying the debris in many of these valleys are more than 
50 feet below the present stream beds. The presence of so much 
filling in all the principal valleys is regarded as an indication that the 
stream gradients have been lowered either by a general sinking of the 
land in the eastern part of the highland area or by rising of the land 
in the western part. It is also possible that the alternate cutting and 
filling of the valleys may have resulted in part, at least, from changes 
in stream flow due to changes in climate. 

San Luis Rey Valley. — San Luis Rey River rises in Warners Valley 
at the foot of Palomar Mountain and flows southwestward over a 
sandy bed to the west corner of the valley, where it turns sharply 
to the northwest and enters a narrow and deep canyon which skirts 
the foot of Smiths Mountain. The river flows on a rocky bed from 
the point where the canyon becomes wider and contains a deposit of 
valley fill over which the stream flows. From the Rincon Reservation 
to Bonsall, near the western side of the highland area, the valley of the 
San Luis Rey contains deep deposits of valley fill, and from Rincon 
to the east side of Monserate ranch the stream has cut an inner canyon 
about 200 feet deep through valley fill. The explanation of this 
condition is that at an early period, while the land was rising, the San 
Luis Rey cut its bed to a position considerably below the present 
bed; that subsequently the land was depressed and this valley was 
filled by the river with rock debris to a level about 200 feet above the 
present stream, and that the land was again elevated so that the river 
cut down through the fill to its present position. 

The total fall of the San Luis Rey from its headwaters to the edge of 
the coastal belt is 2,675 feet, or an average of about 60 feet per mile. 
The fall is everywhere only about 35 feet per mile except between the 
west corner of Warners Valley and the Rincon reservation. Between 
Warners Valley and Pala the San Luis Rey receives no tributaries 
from the south. All the area south of this part of the river drains 
southward to the Santa Maria. 

San Dieguito Valley. — San Dieguito River, which is called Santa 
Ysabel Creek in its upper course, rises on the southwest slope of 
Volcan Mountain, one branch heading in the south corner of Warners 
Valley, and flows in a fairly direct southwesterly course to the ocean. 
The streams that form its headwaters occupy narrow canyons 
developed along a fault line, the southwest wall of the canyons being 
a continuation of the southwest wall of Warners Valley. The drain- 



tk 




PHYSIOGKAPHY. 39 

age on the north side of Santa Ysabel Creek reaches it through short 
parallel streams that flow almost due south; that on the south side of 
the creek, however, does not enter the main stream directly but forms 
Santa Maria Creek, which flows parallel to the Santa Ysabel through 
the Santa Maria plain and joins San Dieguito River in San Pasqual 
Valley. Through a large part of its course the main stream flows 
over valley fill, but it has not cut so deeply into the fill as has the 
San Luis Rey in part of its valley. 

San Diego Valley. — San Diego River rises on the table land near 
Julian, and all its headwaters flow west or northwest until they reach 
the deep canyon through which the main stream flows and which 
extends southwestward. Above El Cajon Valley no large streams 
enter the river on the north side, but on the south it receives many 
streams of considerable size. The area lying immediately north of 
the San Diego is drained by San Vicente Creek, which flows in a 
course roughly parallel to that of the San Diego, to its junction with 
the latter near Lakeside. 

Sweetwater Valley and other valleys. — Sweetwater Valley and the 
valleys of Cottonwood and Pine Valley creeks, in the southern part 
of the area, are essentially like the valley of the Santa Ysabel. Sweet- 
water River rises just east of Cuyamaca Peak, on a table-land into 
which its headwaters have cut deep canyons, and flows southwest- 
ward to the ocean in a course parallel to courses of the Santa Maria 
and the San Dieguito. Between the headwaters and Dehesa the 
river receives several tributaries of considerable size on the south 
side but none at all on the north side, all the country between Sweet- 
water Valley and San Diego River being drained by tributaries of the 
San Diego. 

Cottonwood Creek, to which Pine Valley Creek is tributary, rises 
somewhat farther south than Sweetwater River and flows in a more 
southerly direction to the eastern base of the San Ysidro Mountains 
where it joins the Rio del Tecate to form Tia Juana River. 

The fall of Sweetwater River between its head and Sweetwater 
dam is 4,300 feet, or nearly 100 feet per mile. The fall between the 
head of Pine Valley Creek and the junction of Cottonwood Creek with 
Rio del Tecate is about 4,000 feet, or about 70 feet to the mile. 

Peculiarities of drainage systems. — The drainage of the highland 
area as a whole presents a number of striking peculiarities. In all 
the principal valleys there are places where the bedrock floor is 
deeply buried beneath detritus. In several of the valleys the streams 
are flowing on the rock bottoms of narrow gorges at places farther 
downstream than those where there is so much filling. In some of 
the latter places the rock floor beneath the filling is so low as com- 
pared with the bottoms of the rock gorges farther downstream as to 
indicate either that the filled parts have sunk as compared with the 



40 GHOUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

gorges or that the gorges have been raised as compared with the filled 
parts, or, in other words, differential land movements have taken 
place. The drainage basins are unsymmetrical, so that most of the 
streams have more and longer tributaries on one side than on the 
other. This arrangement may have resulted from tilting of some of 
the blocks of the earth's crust as they were raised or lowered. 

The pattern of the streams, as drawn on a map, shows that there 
is a tendency in parts of the region for the drainage to follow nearly 
parallel courses and to make rectangular changes of direction. These 
conditions are believed to be due to control of the drainage by faults 
or other structures in the rocks. 

AN ANCIENT RIVER VALLEY. 

It is believed that previous to the establishment of the present 
drainage systems at least the central part of the highland area was 
drained by an ancient stream a part of whose course is now indicated 
by a line of stream deposits (see PL III, in pocket), that extend from 
Witch Creek southwestward nearly to Foster. The evidences of 
this old drainage line are described by Fairbanks * as follows : 

It is not generally known that an acient auriferous gravel channel exists in the 
county. It begins about a mile north of the old stage station, and 3 miles west of 
Ballena post office, where there rises a hill shaped like a whale's back (hence the name 
Ballena), covered with washed gravel and boulders. The main portion of the channel 
which has escaped erosion begins south of the stage station, capping a hill which 
has an elevation above the sea of 2,400 feet, being a little lower than the so-called 
Whale Mountain. The gravel is 50 to 100 feet thick, and has a width of 2,000 feet or 
more. It rises 300 to 500 feet above the valleys and canyons on its sides. It extends 
in a direction a little south of west for about 4 miles, terminating on the south of 
Santa Maria Valley. A granite ridge runs 2 or 3 miles farther in the same direction, 
probably preserved by the gravels, which are now gone. A pretty valley, a mile long, 
has been eroded in the eastern end of the gravels, down to the underlying granite. 
Placer mining has been carried on for years here in a small way by Mexicans. Gold 
is said to be scattered everywhere through the gravels, which are often very firmly 
cemented . Lack of water, for the ridge is higher than any of the surrounding country, 
has prevented work on a large scale. Lately a mining district has been organized, and 
it is proposed to bring water 7 miles in pipe. In the gravels are washed boulders, 
many of them being 2 feet in diameter and well polished. The remarkable thing 
about them, however, is that they are nearly all porphyries. The most abundant is 
a red feldspar-quartz porphyry. Quartzite boulders of all colors are numerous, and 
there are a few of the basic diorite so common in portions of the county. Garnets are 
said to be very abundant in the gravels, and many boulders of a schist carrying them 
are also present. The matrix of this rock could not be made out in the field ; it is very 
tough and heavy, and has never been seen in place. The red porphyry boulders 
resemble those on the mesa farther west, but have never been found in place. Never, 
in the mountains east or north, has porphyry of this kind been seen, either by myself 
or described by others. From the old stage station the upper course of the stream was 
north and south as far as it can be traced. There are indications that one branch 



1 Fairbanks, H. W., Geology of San Diego County, also of portions of C range and San Bernardino coun- 
ties: California State Min. Bur. Eleventh Ann. Rept., pp. 91-92, 1893. 






PHYSIOGRAPHY. 41 

extended easterly toward Julian. These gravels appear on a hill surrounded by deep 
canyons, about 2 miles east of the top of the grade above Fosters. At the top of the 
grade the hills on the west are flat-topped, and covered with gravels to a depth of 150 
feet. These have much the same character, and probably belong to the same channel . 
More investigation is needed to, determine whether the course of the old stream was 
down toward the San Diego River, in Cajon Valley, or west toward the high mesas 
south and southeast of Poway Valley. It seems probable, however, that the stream 
flowed west, and that the mesas have been formed partly from the bowlders which 
they brought down. This mesa, as well as the gravels at the head of the grade, has an 
elevation of 1,500 feet. The source of the porphyry boulders and the garnetiferous 
schists of this old river is a matter of great perplexity. The gravel deposit has every 
characteristic of an old river channel, and not that of an elevated arm of the sea; 
besides, the presence of gold in the gravels indicates their derivation from the country 
farther east. The gold may have been derived from Julian or Mesa Grande, or some 
more remote point. The river must have flowed across the gold belt, but then the 
question arises, how could a river of such magnitude have existed so near the summit? 
The only way out of the difficulty is to suppose that a great uplift has taken place 
along the crest and western slope, coupled with an enormous amount of erosion; and 
that this stream once, before this great change took place in the configuration of the 
country, headed many miles to the northeast, far beyond the drainage of the western 
slope. The boulders consist largely of hard rocks, and are very smoothly rounded and 
polished, indicating that they have been transported a long distance, and subjected 
to attrition through a protracted interval. 

The peculiarities of the present drainage system, together with 
the evidence of an earlier drainage, indicate not only that the land 
surface in this area has undergone changes of level of considerable 
magnitude but also that these disturbances have been accompanied 
by warping and slight differential movements of the crust which 
have produced faults and folds throughout the area. It is probable 
that many of the present drainage lines have been developed in part 
along depressions created by crustal movements and in part along 
fault lines and zones of crushed and weakened rocks, caused by those 
movements. 

HIGHLAND BASINS. 
GENERAL FEATURES. 

Comparatively flat tracts, some of them surrounded by steep 
mountain walls, cover many square miles within the highland area 
and form the broad valleys or basins that are referred to in this 
report as highland basins. El Cajon Valley (PL XIII), Santa Maria 
Valley (see fig. 2), and Warners Valley are typical examples. They 
bear about the same relation to the stream valleys that lakes ordi- 
narily bear to rivers — that is, they form nodes or local enlargements 
which in size are out of proportion to the main stream valleys. Thus 
El Cajon Valley, a little more than halfway between the head and 
mouth of San Diego River, forms a broad, nearly square basin that 
extends 6 miles in the direction at right angles to the course of the 
river and more than 5 miles in the direction parallel to the river. 
The river valley both above and below this basin is in most places 



42 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 




less than a quarter 
of a mile wide and 
does not exceed 
three-quarters of a 
mile in width even 
in Mission Valley, 
near the mouth of 
the river. 

The floors of 
these valleys are 
comparatively 
smooth and slope 
gently toward the 
streams to which 
they are tributary, 
being in this respect 
distinctly in con- 
trast to their rug- 
ged surroundings. 
Thin deposits of al- 
luvium, with minor 
amounts of wind 
deposits, underlie 
all parts of these 
basins, except in 
Warners and San 
Felipe valleys, 
where lake deposits 
occur. In the cen- 
tral parts of the ba- 
sins, where the al- 
luvium has been 
spread out by flood 
waters, it ranges in 
thickness from only 
a few inches to sev- 
eral feet, but in the 
slopes near the bor- 
ders of the basin 
the thickness of the 
deposit may be 30 
feet or more. The 
alluvium is under- 
lain by granite, 
which is thoroughly 



PHYSIOGEAPHY. 43 

disintegrated at the surface, but becomes gradually firmer below the 
surface and is solid at a depth ranging in general from 50 to 100 feet. 
At some places south of Fallbrook this residuum is not more than 
10 feet thick, and at a few places, especially northwest of Escondido, 
fresh granite outcrops at the surface. 

Each of the highland basins is crossed by one or more streams, but 
there is apparently no genetic relation between the streams and the 
basins. San Diego River flows along the northern edge of El Cajon 
Valley; the headwaters of San Luis Rey River lie in the extreme 
northern part of Warners Valley, and in the lower part of its course 
this stream crosses near the middle of Fallbrook Plain; Escondido 
Creek crosses near the north end and San Dieguito Creek near the 
middle of the Escondido plains; and Los Penasquitos Creek flows 
along the south wall of Poway Valley ; and there is no clear evidence 
that the general topography of any of the basins is due to erosion 
by these streams. 

In accordance with their geographic distribution, the highland 
basins are grouped into three belts. The first belt, or lower basins, 
includes Fallbrook Plain, Escondido, Poway, and El Cajon valleys. 
Poway Mesa is also included in this belt of basins, because the rock 
floor on which the deposit that now forms the mesa was laid is 
believed to be similar to and genetically related to the basin floors 
on the north and south of it. The second belt, or intermediate 
basins, includes Bear Valley and Santa Maria Valley;* and the third 
belt, or higher basins, includes Warners and San Felipe valleys. 

LOWER BELT. ' 

FaUbrook Plain. — Fallbrook Plain extends from Santa Margarita 
River, at the foot of Gavilari and neighboring mountains, southward 
to the valley of the San Luis Rey, and from Red Mountain westward 
to the eastern edge of the sedimentary rocks underlying the coastal 
belt. Its surface is gently rolling, but a few hills are scattered along 
its western edge. The bedrock is principally granite, which is 
decomposed at the surface, the residuum being 50 to 100 feet deep 
over most of the area, but only a few feet thick or entirely absent 
in some places, where fresh rocks lie near to the surface or are 
exposed. The elevation of Fallbrook Plain ranges from 500 feet to 
about 700 feet, the mean elevation being about 600 feet. 

South of Fallbrook Plain and separated from it by the valley of 
the San Luis Rey another basin extends southward to San Marcos 
Creek and from San Marcos Mountains westward to the sedimentary 
rocks. This basin was originally of the same character and origin 
as Fallbrook Plain, although it has been made more rugged by ero- 
sion by the headwaters of seven or eight small streams that rise at 
the foot of San Marcos Mountains. The surface is covered by resid- 



44 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

num., and the average elevation is about 500 feet. At its southern 
end this basin swings eastward along the northern base of Cerro de 
las Posas and joins Escondido Valley, where, owing to less favorable 
conditions for stream erosion, the surface becomes much smoother 
Escondido and Poway valleys. — Escondido Valley is bounded on the 
north by the south ends of the San Marcos Mountains, Merriam 
Mountains, and Burnt Mountain, and extends southward (including 
Poway Valley) to Los Penasquitos River and the base of the cliff of 
Tertiary gravels that forms the side of Poway Valley. It is 4 to 8 
miles wide. On the east it is bounded by highlands that are more 
than 2,000 feet in elevation and that include Las Lomas Muertas and 
Woodson mountains, and on the west by Mount Whitney, Black 
Mountain, and intermediate peaks. The topography of this basin is 
not essentially different from that of Fallbrook Plain, though the 
mountain wall on the west gives it a more basin-like appearance. 
The surface is much smoother in the vicinity of Escondido than 
elsewhere owing to deposits of alluvium which have filled many of the 
hollows. The surface rises slightly between Escondido and Poway, 
becoming rougher, like the area between the San Luis Rey and the 
San Marcos, and it is crossed by San Dieguito River, which has cut a 
narrow valley to the depth of about 400 feet below the level of 
Escondido. Twin Peak, rising to an elevation of 1,312 feet, and sev- 
eral lower granitic hills in its vicinity nearly separate Poway Valley 
from the northern part of the plain. The mean elevation of Escon- 
dido Valley is about 700 feet, and of Poway Valley about 500 feet 
above sea level. 

The formation that lies at the surface over the greater part of the 
basin is residuum popularly known as decomposed granite. It 
extends to depths of from 40 to about 100 feet, and is underlain by 
solid granite. Along Escondido Creek beds of sand and gravel that 
occupy an old rock valley of the stream have been penetrated to 
depths of 30 to 40 feet by well borings that have failed to reach 
bedrock. 

Poway and El Cajon valleys are separated by Poway Mesa, which 
is 1,000 to 1,200 feet in general elevation and is underlain by coarse 
gravels mixed with more or less sandy clay that stand in steep slopes. 
These gravels form most of the north slope of El Cajon Valley, and 
along this slope granite can be seen underlying the gravels at an eleva- 
tion about 500 feet above the sea. The Beaver oil well (K 22, PL II 
and p. 68) was drilled almost exactly in the center of Poway Mesa at an 
elevation of 1,000 feet above sea level, and it was reported that granite 
was reached at a depth of about 800 feet. According to this informa- 
tion the elevation of the bedrock at this point between Poway and 
El Cajon valleys is about 300 feet above sea level. The position of the 
rocks here and under the gravels north of San Diego River indicates 



PHYSIOGKAPHY. 45 

that there is no important break in the surface of the rock floor 
between Poway and El Cajon valleys. 

Practically all the material penetrated by the Beaver oil well 
consisted of the gravels and sandy clays that are exposed in all the 
canyons in the Poway Mesa, but immediately overlying the bedrock 
the well encountered a deposit that probably corresponds to the marl 
in El Cajon Valley. If the meager information in regard to this 
material is correctly interpreted it indicates that previous to the 
deposition of the gravels of the mesa the underlying rock surface was 
submerged in the waters of a bay which for a long time was receiving 
very little sediment from the land on the east. 

El Cajon Valley — El Cajon Valley, which has a mean elevation of 
about 500 feet, is bounded on the north by Poway Mesa, on the east 
and south by granite walls that rise 500 to 1,500 feet above the valley 
floor, and on the west by a steep, wave-cut slope composed of Ter- 
tiary deposits. At least six terraces are preserved along this western 
wall at elevations of about 440, 570, 650, 688, 760, and 800 feet above 
sea level, respectively. Cowles Mountain, through which San Diego 
River has cut a gorge, forms a short stretch of the west boundary. 
This valley is not unlike the basins previously described, the only 
noteworthy difference being that, except where cut by the narrow 
gorge of San Diego River, it is completely inclosed by high walls, 
and from this fact it derives its Spanish name, meaning "the box." 
The length of the valley north and south is about 5 miles, and the 
average width east and west about 4 miles. A thin layer of alluvium 
covers the surface, but under this residuum or decomposed granite, 
in places extending to depths of 25 to 50 feet, has been encountered 
in a number of wells. At several places in this valley, however, 
wells passing through the alluvium at the surface have entered a 
calcareous clay resembling marl, which along San Diego River west 
of Lakeside was found to be more than 200 feet thick. This material 
is believed to have been deposited in quiet waters that occupied 
El Cajon Valley before and during the time that the gravel and clay 
of Poway Mesa was being deposited. That El Cajon Valley was not 
deeply filled by Tertiary deposits and later excavated by erosion is 
indicated by the absence of any identifiable remnants of such deposits 
along the eastern and southern walls of the valley and on the valley 
floor itself, and by the absence of any stream competent to remove so 
completely so large an amount of material. It is therefore concluded 
(1) that comparatively little sedimentation took place in the basin 
while it was submerged, and that Tertiary deposits along the west 
side were distributed by shore currents, and (2) that the distribution 
over this valley of the deposits which form Poway Mesa as well as 
other high terraces was prevented by the headland formed by San 
Miguel Mountain and the islands offshore, comprising what are now 



46 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Cowles Mountain, Black Mountain, Mount Whitney, and inter- 
mediate peaks, which directed the shore currents along their western 
sides. 

When the land was elevated Ihe bays were gradually drained, the 
water which occupied El Cajon Valley escaping through the narrow 
passage now occupied by San Diego River; and the terraces on the 
west wall of the valley indicate the successive stages of uplift while 
the waves in the bay were washing against the steep wall of sediments. 

Origin of the basins of the lower belt. — All the highland basins thus 
far described, together with the rock surface underlying the gravels 
of Poway Mesa form a belt which may be regarded as a structural 
unit. The gravels of Poway Mesa are evidently marine deposits, as 
is indicated by their position and structure. At the time of their 
deposition the underlying c^stalline rock basement was submerged. 
El Cajon Valley and Poway Valley were submerged at this time, 
together with the marls of marine origin underlying it, and by the 
marine deposit on the northwest side of Poway Valley; but no direct 
evidence that Escondido Valley and Fallbrook Plain were submerged 
has been obtained. No evidence was discovered in this area indi- 
cating that these basins might have been produced by marine erosion 
before the deposition of the gravels, but this present lack of evidence 
is not considered sufficient reason to abandon altogether the theory 
of marine erosion, and further study of this problem is highly desir- 
able. However, other features of the highland area afford evidence 
that this surface is a part of a more extensive base level, and that it 
owes its present position relative to the adjacent highlands on the 
east to the earth movements which have characterized the geologic 
history of this region. 

INTERMEDIATE BELT. 

Approximately parallel to the belt of basins previously described 
and about 10 miles east of it there is a second belt of basins that show 
the same similarities in geology and topography that have been 
pointed out in regard to the western belt. This belt includes Bear 
Valley and the broad area of low relief that extends 5 or 6 miles 
northward nearly to the Pauma grant, the south half of the Guejito 
grant, and Santa Maria Valley. The basins in this belt are from 
1,000 to 1,500 feet higher than those in the first belt, and they are 
more definitely separated by deeply eroded canyons. Nevertheless, 
they correspond very closely in their physical features and were 
obviously connected previous to the development of the canyons 
which now separate them. 

Bear Valley. — The area lying south of the Pauma grant and includ- 
ing Bear Valley is an elevated table-land about 1,500 feet above sea 
level, very irregular in outline but definitely bounded in every direc- 
tion except the southeast by deep valleys and sharp peaks and ridges, 
whose summits correspond in elevation with the general level of this 



PHYSIOGKAPHY. 47 

area. Alluvium and residuum underlie the surface except where 
small rocky hills rise above the general level. In the southern part 
of the area is a deposit of valley fill, the extent and thickness of which 
was not ascertained, but it is neither so thick nor so extensive as the 
fill in El Cajon Valley or in Escondido Valley. 

From the eastern end of Bear Valley the land surface rises gradually 
to the boundary of the Guejito grant, where it reaches a broad rolling 
table-land, 2,000 feet above sea level, that comprises about 7,000 
acres, and extends 8 miles southward to San Pasqual Valley. The 
physical features of this basin are essentially like those of the area 
previously described. It is bounded on the north by Roderick 
Mountain and Pine Mountain, which rise to elevations of about 3,800 
and 4,100 feet above sea level, respectively, but on the east and south 
it is bounded by deep valleys. On the west there is a broad area of 
very rugged topography but the summits of the peaks correspond in 
general elevation with this plain. 

Santa Maria Valley. — Santa Maria Valley is separated from the 
Guejito basin by the canyon of Santa Ysabel River and San Pasqual 
Valley, which have been cut to a depth of about 1,000 feet below the 
level of Santa Maria Valley. The mean elevation of Santa Maria 
Valley is about 1,500 feet. Its surface is gently rolling and is formed 
by alluvium and decomposed granite, except along the course of 
Santa Maria Creek, which crosses about the middle of it, where sand 
and gravel of fluviatile origin occur. This basin is roughly circular 
in outline and is approximately 6 miles in diameter. It is bounded 
by broken country of high relief distinctly in contrast to the topog- 
raphy of the valley itself, in which granite hills that rise to elevations 
500 to 1,000 feet higher than Santa Maria Valley are common. 

Just east of this basin and separated from it by a narrow belt of 
rough country there is an area similar in character and nearly as 
large, which stands at an elevation of about 2,300 feet. This area 
includes Santa Teresa Valley. It is more indefinite in outline and 
somewhat rough, but its surface is distinctly more even than that 
of the country surrounding it. 

Other basins. — In the southern part of the highland area there are 
a large number of smaller basins similar to those just described. 
Some of them are very definitely bounded by mountain walls; for 
example, Jamul Valley (elevation, 1,000 feet), whose sharp triangular 
shape is a striking feature, and Padre Barona Valley (elevation, 
1,500 feet), which, although closely surrounded by high peaks and at 
least 500 feet above the base-level of its small drainage system, has a 
floor so nearly flat that it is almost marshy in places. Other basins 
are irregular and more or less indefinite in outline and stand at eleva- 
tions successively higher from the edge of the coastal belt eastward 
to the divide. 



48 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIE. 

HIGHER BELT. 

East of Bear and Santa Teresa valleys is a third beit of character- 
istic basins which includes Warners, San Felipe, Dodge, and Oak 
Grove valleys. Of this group only Warners Valley was studied in 
the field, but the topographic map shows that all correspond rather 
closely in elevation, and particularly that Warners Valley and San 
Felipe Valley are essentially the same in their topographic relations 
to their surroundings. The logs of a few wells in San Felipe Valley 
and some general information in regard to that area (p. 206) support 
the topographic evidence. 

Warners Valley is nearly square and comprises about 32 square 
miles. It is bounded on all sides by steep mountain walls that rise 
on the east, south, and west more than 1,000 feet, and on the north 
more than 3,000 feet above the valley floor. The valley floor com- 
prises areas of rolling land, flat river floodplains, and a small group 
of low rocky buttes, called Monkey Hill, which lies a short distance 
from the southwestern side of the valley. Some granitic residuum 
occurs in the valley but most of the valley floor is formed by sediments 
that were deposited in an ancient lake. Shore features, beach ridges, 
deltas, and terraces, composed largely of gravel formed in this lake 
are preserved on all sides of the valley but are most definite on the 
northeastern, southeastern, and southwestern borders. The north- 
eastern and southwestern edges of the valley coincide with fault 
lines, as shown by the California Earthquake Commission, 1 and 
characteristic evidences of faulting are displayed along the south- 
western edge. It seems probable also that the valley is bounded on 
the northwest and southeast by faults, and that it was produced by 
faulting. 

ORIGIN OF HIGHLAND BASINS. 

The correspondence in the elevations of the basins in each of the 
three belts has been pointed out, and also the fact that the belts are 
successively higher from the coastal region eastward. There is, 
moreover, in all of the region lying east of the first belt of basins, a 
notable correspondence in elevation between the summits of most 
of the peaks in the broken areas and the basins. In fact, if, in the 
region east of Escondido and El Cajon valleys, all the canyons were 
filled up level with the basins of the highland belt there would be 
reconstructed an extensive rolling plain sloping gently toward the 
west. Along the eastern border of the area this plain would be 
broken by a range of mountains, including Palomar, Volcan, and 
Cuyamaca peaks, but farther west the summits of most of the peaks 
and ridges would coincide with the plain, so that only widely separated 
buttes would rise considerably above the general level. On the west 

1 Rept. California State Earthquake Commission, Andrew C Lawson, chairman, 1910, Atlas, Map. No. I. 



PHYSIOGRAPHY. 49 

this plain would be level with the summits of Monserate Mountain, 
the San Marcos and Merriam mountains, and with the heights all 
along the eastern borders of Eseondido, Poway, and El Cajon valleys, 
but along the eastern edge of the first belt or lower basins it would 
suddenly end and the surface would fall in steep slopes 500 feet or 
more to the level of the Fallbrook, Eseondido, and El Cajon basins. 

These relations indicate that in an earlier geologic time a plain of 
this kind really existed here, that the present high, flat areas so 
widely distributed throughout the region are remnants of it, and that 
the present topography is due principally to stream erosion which 
progressed gradually as the region was elevated from its original 
low position to its present altitude. But as a result of a certain 
amount of faulting that took place while the land was being raised 
some land masses were elevated more than others. Thus Palomar 
Mountain and Volcan Mountain and some of the other peaks were 
raised high above their surrounding regions. According to Merrill 1 
(see p. 37) faulting and folding have probably been important 
factors in the development of the present topography of the high- 
land area. He states that this "is an anticlinal area including 
iii 1 ' nor synclines. The various anticlinal and synclinal folds are 
intersected by parallel faults at right angles to their axes and conse- 
quently with northeast trend. These faults have cut the formation 
into blocks which pitch northwesterly." The differential elevation 
and tilting of fault blocks west of Smiths Mountain and Cuyamaca 
Mountain have not been so directly instrumental in producing the 
present topography as erosion has been; but indirectly by their 
effect on drainage, as suggested on page 37, they have probably 
been influential throughout the entire region. The presence of 
faults along the western edge of the highland area has not been 
established, but considering the general topographic and structural 
relations of the region as a whole and the present lack of definite 
indications of marine erosion in the basin areas, it seems extremely 
probable that the Fallbrook, Eseondido, Poway, and El Cajon 
basins, and the rock basement of Poway Mesa, were originally parts 
of the extensive base level on the east, and if they were it is impossible 
reasonably to account for their present topographic relation to the 
highlands on the east except by the theory that, as a result of faulting 
or exceedingly sharp folding along their eastern borders, the land 
surface on the east was raised nearly 1,500 feet higher than it was 
west of those borders. 

The range of mountains along the western edge of the highland 
area, including Otay, San Miguel, Cowles, and Black mountains, was 
probably brought into relief primarily by erosion previous to the 

i Merrill, F. J. H., Geology and mineral resources of San Diego and Imperial counties: California State 
Min. Bur. Biennial Rept., 1913-14, p. 8, 1914. 

115536°— 19— wsp 446 4 



50 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

elevation of the land farther east and, like the range including 
Cuyamaca and Laguna mountains, rose to a considerable height 
above the ancient base level, but it seems also to have been involved 
to some extent in differential crustal movements which may have 
included faulting, as is indicated by the fact that all the large streams 
cross this range through rock gorges floored with solid rock, whereas 
immediately east of the range these streams flow over debris-filled 
valleys whose rock bottoms lie much lower than the rock floors of 
their canyons through the felsite range. 

GEOLOGY. 

By A. J. Ellis. 
GENERAL STATEMENT. 

The area discussed in this report is divisible geologically into two 
provinces, one, comprising a region of crystalline rocks that extends 
from the eastern boundary of the area westward to the coastal 
section, practically coextensive with the highland area, and the other 
a region of sedimentary rocks that lies between the region of crystal- 
line rocks and the ocean and is practically coextensive with the 
San Diego coastal belt. The boundary between these two provinces 
is a sinuous line roughly parallel to the coast at an average distance 
of about 15 miles inland. Throughout most of its length, and 
especially in the southern part of the area, where the edge of the 
crystalline rocks is marked by a range of mountains, the boundary 
is sharply denned by the abutment of the flat-lying sediments 
against steep walls of igneous rocks; but in most places, particularly 
in the northern part of the area, the sedimentary rocks overlap on 
the crystallines in such a way that the establishment of a boundary 
line between the two is more or less arbitrary. There are a few out- 
lying masses of crystalline rocks in the sedimentary area (PL XIV, B), 
and scattered deposits of unaltered sediments occur in the crystal- 
line area. Slates, quartzites, and schists of sedimentary origin are 
present in the crystalline area, but are so intimately associated with 
the granites and felsites that they are regarded as elements of the 
crystalline complex. 

SEDIMENTARY FORMATIONS. 
DISTRIBUTION AND CHARACTER. 

The San Diego coastal belt has been the scene of deposition through 
a very long time. A drill hole near San Diego, which was begun prac- 
tically at sea level, has penetrated sedimentary rocks to a depth of 
more than a mile, and more than a thousand feet of stratified deposits 
lie above sea level. On the east the sedimentaries overlap the 



GEOLOGY. 



51 



crystalline rocks and become rapidly thinner until they disappear, 
but on the west they extend to an unknown depth. The formations 
consist of conglomerate, sandstones, shales, and limestones, but, 
owing to the close proximity to the highland area from which nearly 
all the material has been derived, coarse deposits are present in large 
proportions and in the upper part of the section they are predomi- 
nant. Some of the finer-grained beds contain fossils, most of them 
poorly preserved and difficult to identify, but fossils of Cretaceous, 
Tertiary, and Pleistocene age have been distinguished. The oldest 
or Cretaceous beds are exposed in only a few low places along the 
coast. The widely distributed terrace formations are of Tertiary 
age. The Pleistocene occurs as a thin veneer on the older rocks 
along the shore. 



Table 1. — Sedimentary formations in the San Diego area, Calif. 



System. 


Series. 


Formation. 


Material. 


Thick- 

ness(feet). 




Recent. 


Valley fill 


Loam, sand, silt, and gravel. . . 


0-100-200 










Pleistocene. 


San Pedro formation 


Beach sands and mud 

Coarse valley fill conglomerate. 


0-50± 


Quaternary. 
Unconformity- 


Pala conglomerate (relation to 
San Pedro formation unde- 
termined; may be contem- 
poraneous with San Pedro 
or may be older). 


0-200+ 


Pliocene and 
Miocene. 






0-50 






Interbedded sandstone, sandy 
marls, sandy shales, and 
conglomerates. 

Conglomerate, thin sand and 
clay beds. 

Breccia 


0-500 


Tertiary. 


Poway conglomerate (rela- 
tion to San Diego formation 
undetermined; may be con- 
temporaneous with San 
Diego). 

San Onofre breccia 


0-1,000 
(?) 










Eocene. 




Sandstone, shale, and lime- 
stone. Thin coal seams. 


600-700 


Cretaceous. 


Upper Cre- 
taceous. 






(?) 









CRETACEOUS SYSTEM. 
CHICO FORMATION. 

The lower parts of the sea cliffs at the south end of Point Loma 
expose beds of dark shales and sandstones from which Fairbanks 
obtained about 60 species of Cretaceous fossils, most of which are 
characteristic of the Chico formation of the Upper Cretaceous. The 
exposed thickness of these beds is estimated at about 50 feet, but 
the estimate may be only roughly approximate, for the Cretaceous 
beds do not differ markedly in appearance from the overlying Ter- 
tiary, and the barrenness of many of the beds made it impossible 
accurately to determine the position of the contact. The Chico 
formation in this locality is overlain by Tertiary deposits that cor- 



52 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

respond in appearance much more closely with the later Tertiary or 
Miocene deposits back of San Diego than with the earlier Tertiary or 
Eocene deposits in the northern part of the area. Fossils indicating 
the age of beds in the upper part of this section could not be obtained, 
but there is little doubt that Eocene formations are entirely absent. 
About a mile north of the point, however, on the east side of the 
peninsula, the lower parts of the bluff expose sandstones which re- 
semble the Eocene sandstones north of Los Penasquitos Canyon, 
and Eocene fossils have been found on the north end of Point Loma, 
so that apparently the later Tertiary was deposited unconformably 
on the underlying formations. Cretaceous beds that are similar to 
those on Point Loma and that carry similar fossils are exposed in 
the sea cliffs at La Jolla, but from La Jolla the beds dip both north- 
ward and southward and disappear within a short distance. Here 
also Cretaceous beds appear to be overlain by later Tertiary de- 
posits, although Eocene beds are exposed in the cliffs a short distance 
north of La Jolla and at the mouth of Rose Canyon southeast of La 
Jolla. In both places the Cretaceous beds are exposed only in sea 
cliffs, and not at the surface, consequently in those places this forma- 
tion is not shown on the geologic map (PI. Ill, in pocket). 

The area of Cretaceous rocks mapped as Chico formation in the 
northwest corner of the county was not surveyed in connection 
with the investigation here reported, but information furnished by 
R. T. Hill and E. S. Larsen, jr., indicates it as the probable extension 
of an area of Cretaceous rocks lying immediately north of this area. 

TERTIARY SYSTEM. 
DISTRIBUTION. 

Two divisions of the Tertiary which are distinguished by lithologic 
as well as paleontologic difference have been recognized in this area — 
an earlier Tertiary, which is undoubtedly Eocene, and a later, which 
appears to be an inseparable assemblage of upper Miocene and Plio- 
cene deposits. Both upper Miocene and Pliocene fossils have been 
obtained in the southern part of the area, but owing to the lack of 
continuity in the strata and to the barrenness of the beds in so many 
places, detailed correlation has not yet been possible, and no general 
stratigraphic distinction between Miocene and Pliocene has been 
made in this report. 

As shown on the geologic map (PI. Ill, in pocket), the earlier Ter- 
tiary or Eocene deposits appear at the surface from Los Penasquitos 
Canyon northward to Buena Vista Creek; the later Tertiary deposits 
are exposed from Las Penasquitos Canyon southward to the Mexican 
boundary and from Buena Vista Creek northward to the north 
boundary of the county. 



GEOLOGY. 53 



EOCENE SERIES. 



The earlier Tertiary or Eocene beds appear at the surface between 
Los Penasquitos Canyon and Buena Vista Creek and underlie the 
later deposits from Los Penasquitos Canyon southward, being 
exposed at low levels in Soledad, San Clemente, and Rose canyons. 
Fossils, possibly of Eocene age, were collected near the top of the 
mesa east of Chula Vista, and although none but late Tertiary de- 
posits have as yet been definitely recognized, detailed paleontologic 
studies may establish the presence at the surface of Eocene deposits 
south of Mission Valley. 

The top of the Eocene is characterized by a white sandstone, which 
in some places east of Delmar and Encinitas is nearly ICO feet thick. 
This white sandstone is underlain by alternating layers of shale, sand- 
stone, and limestone, all of which, in contrast with the later Tertiary 
deposits, appear to be quite uniform over considerable areas. In the 
upper part of the section limestone is rare and the sandstones and 
shales are generally very light colored, the shales being usually 
decidedly greenish; but in the lower part of the section, as exposed 
along the shore line, the beds are somber colored, some of them very 
dark, and thin layers of limestone are common. 

The following section is exposed in the sea cliffs 2 miles north of 
Delmar and just north of the mouth of San Dieguito River. The 
beds are undulating, but near the southern end of the exposure they 
dip 5° N. 25° E. 

Section 2 miles north of Delmar. 
Pleistocene: Feet. 
Yellow and reddish, slightly indurated sand, containing Pleisto- 
cene fossils 40 

Eocene : 

Yellow to white sandstone 20 

Shale; thin layers; greenish with rusty patches; contains a few 

fossil oysters 8 

Limestone composed chiefly of oyster shells 6 

Greenish-white sandstone 3. 5 

Limestone composed chiefly of oyster shells 3 

Greenish sandstone with a few thin (1 to 2 inch) streaks of fossil 
oysters , 4 

Among the fossils collected from the uppermost of these beds, 
W. H. Dall identified six Pleistocene forms. (See p. 69.) The basal 
members of the section yielded numerous specimens which Mr. Dall 
labels Ostrea sp. undet. 

The following section is exposed 1 mile south of Delmar at the east 
side of the road near the mouth and on the north side of Soledad 
Canyon. The beds dip 6° 30' N. 30° W. 



54 GKOUND WATEKS OF WESTERN SAN DIEGO COUNTY, CALIF, 

Sections of Eocene beds 1 mile south of Delmar. 

Feet. 

(Top) Friable white sandstone 10 

Shale 6 

Brown to white sandstone 3 

Shale 4 

Brown to white sandstone 3 

Shale 5 

Varicolored sandstone — red, yellow, and white 3 

Greenish shale, somewhat sandy 5 

The following section is exposed 2 miles southeast of Delmar, on 
the east side of the railroad, at the mouth of Soledad Canyon. The 
beds dip 6° 30' N. 75° W. 

Section 2 miles southeast of Delmar. 

Feet. 
Pleistocene: Silt, gravel, and pebbles, with Pleistocene fossils. 

Eocene: Friable sandstone with pebbles; rough bedded 15 

Eocene : Massive argillaceous sandy layer containing Ostrea sp. undet. 
Greenish sandy shale. 

A richly fossiliferous outcrop of shale, sand, and gravel appears on 
the west side of the county road in the south wall of San Clemente 
Canyon, 6 miles east of its junction with Rose Canyon. The fossils 
collected here were submitted to Mr. Dall, who identified them as 
Eocene, closely resembling in the general assembly the fauna of the 
Arago group at Coos Bay, Oreg., but the species are represented by 
very poor casts, not determinable. The following genera are all 
represented : 

Conus. Acila. Angulus. 

Nassa. Nucula. Solen. 

Turritella. Glycymeris. Diplodonta. 

Trochita. Ostrea. Corbula. 

Hipponix. Cardium. Terebratulina. 

Modiolus. Tellina. Laquens. 

Anomia. Macoma. 

Leda. Moerella. 

In the cliff on the south side of the mouth of San Eli jo Lagoon, 
3 miles south of Encinitas, the following section is exposed. The 
top bed dips 5° E., but the lower beds dip 4° 30' S. 

Section of Eocene beds at mouth of San Elijo Lagoon. 

Feet. 

(Top) Yellow to white sand 30 

Limestone composed of a mass of Eocene shells, a collection of which 
contained, as determined by Mr. Dall: Ostrea sp., Scala sp., Veneri- 
cardia planicosta var. horni Gabb, Pitaria (?) sp., Tellina sp., Ceri- 

thium sp., Ampullina (?) sp., Tochita sp 8 

Yellow sandstone 4 

Sandy limestone containing numerous oysters and a few other fossils. . . .3 
Coarse yellow sandstone with a few scattered oysters at the top 3 



GEOLOGY. 



55 



A well drilled about 5 miles northeast of Encinitas, in sec. 26, T. 
12 S., R. 4 W. (F 6, PL II), in search of oil, penetrated 2,126 feet 
of alternating beds of sandstone, shale, conglomerate, and limestone, 
as shown in the following well log. Eocene sandstones and shales 
immediately underlie the surface where this well was drilled, but it 
is not possible to determine from the reported log the depth to which 
the Eocene rocks extend. The log as given represents some unfor- 
tunately broad generalizations, as, for example, the first 700 feet of 
the section is reported merely as sandstone and shale, whereas a 
detailed record would undoubtedly show a succession of distinct 
beds, but it is especially remarkable that at the depth of 700 
feet an 800-foot bed of conglomerate was encountered. Probably 
this also represents a rough grouping of very distinct layers, and it is 
possible that the other members of the section should also be regarded 
as more or less general. 

Table 2.— Log of Clark oil well (F 6). 
[Authority, K. V. Phoenix. Surface elevation about 200 feet above sea level.] 



Sandstone and shale 

Conglomerate 

Blue shale 

Calcareous layer 

Red shale 

Conglomerate 

Hard black sand 



Thick- 
ness. 


Depth. 


Feet. 


Feet. 


700 


700 


800 


1,500 


125 


1,625 


?Thin 


?Thin 


35 


(?) 


(?) 


1,750 


100 


1,850 



Sandy shale 

Limestone 

" Brea sand" 

Shale 

White sand with sulphur water 
Calcareous shale with fossils. . 
Hard sand layers 



Thick- 
ness. 



Feet. 

25 

35 

105 

(?)1 

64 
(?) 1 

45 



Depth. 



Feet. 
1,875 
1,910 
2,015 
2,016 
2,080 
2,081 
2,126 



Note.— Work on this well was interrupted at the depth of 1,750 feet; when it was resumed the old boring 
was reamed out. Mr. Phoenix was employed on the second stage of the work and during the subsequent 
drilling, and this log was furnished by him from memory. 

The following incomplete log of the Balboa oil well was furnished 
by Mr. H. A. Whitney, of the San Diego Department of Water: 

Table 3. — Log of Balboa oil well (K 37). 
[Surface elevation, 15 feet above sea level.] 



Pleistocene (valley fill): 

Quicksand, gravel, and 

shells 

Sand and boulders 

Eocene: 

Shale, stratified, blue and 

brown 

Hard white shell lime 

Shale (stratified) 

Hard shell [limestone?] . . . 

Water sand 

Shale (mixed strata) 

Hard white shell lime 
[limestone?] 



Thick- 
ness. 



Feet. 



154 
25 
175 

? 

? 
175 



25 



Depth. 



Feet. 



80 
146 



300 
325 
500 
? 
525 
700 

725 



Eocene— Continued. 

Water sand, fine gray, 

water fresh 

Hot fresh water 

Sand, shale, boulders 

Sand, shell [limestone?] 

shale 

Hard shell [limestone?] — 
Brown shale showing oil. . 
Black sand (sulphur water 

with gas) 

Brown shale showing oil. . - 

Hard limestone 

Water sand, brackish 

Blue limestone 



Thick- 



Depth. 



Feet. 


Feet. 


175 


900 


100 


1,000 


226 


1,226 


74 


1,300 


25 


1,325 


625 


1,950 


30 


1,980 


230 


2,210 


37 


2,247 


63 


2,310 


100 


2,410 



GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 






A later record of this well is published by F. J. H. Merrill 1 as 

follows : 

Table 4.— Log of Balboa oil well (K 37) {1913). 

[Surface elevation, 15 feet above sea level.] 





Thick- 
ness. 


Depth. 




Thick- 
ness. 


Depth. 


Pleistocene (valley fill): 

Quicksand, gravel, and 


Feet. 

80 
66 

179 

10 

15 

150 

10 

15 

175 

25 

175 

100 

226 

74 

25 

885 

37 

63 

100 

144 

5 

12 

4 

16 


Feet. 

80 
146 

325 
335 

350 

500 

510 

525 

700 

725 

900 

1,000 

1,226 

1,300 

1,325 

2,210 
2,247 
2,310 
2,410 
2,554 
2,559 
2,571 
2,575 
2, 591 


Eocene— Continued . 


Feet. 

15 

12 
4 

15 
9 
4 

22 
2 
4 

16 
3 

18 
145 
2 
16 
16 
26 
22 

5 
3 

28 
7 

10 
5 


Feet. 
2,606 




2,618 






2,622 
2,637 






Shale, blue and brown 


Shell 


2,646 


Shale... 


2,650 
2,672 
2,674 


Water sand (artesian flow) 


Dark hard lime shell 

Do .'. 






2,678 
2,694 




Dark hard lime shell 




2,697 

2,715 

2,860 


Hard white shell lime 


Alternating shale and 






Sand, shell, and bouldeps . . 




2,862 


Dark-blue lime 


2,878 






2,894 
2,820 


Shale, brown (clay stiff 
enough to stand up) 


Dark-blue lime 


Light-blue lime 


2,942 


Light - blue lime mixed 




2,947 
2,950 
2,978 
2,985 
2,995 


Blue-black limestone gas?o 


Hard black slate and lime. 






Do .'. 


Black slate 




Gray sand rock 


3,000 


Dark-gray, \ cry hard 





a New company began operations here. 

The first 146 feet of the above log represents Quaternary valley 
fill. The underlying formations are no doubt Eocene but the depth 
to which the rocks of this age extend can not be ascertained from 
the log. It is probable that Cretaceous beds are reached at a depth 
less than 1,000 feet. 

As compared with the later deposits, the Eocene beds in this area 
appear to have been laid down in comparatively deep water. The 
bedding is uniform and persistent, and the segregation of coarse and 
fine materials is thorough. Coarse deposits, such as conglomerate, 
are notably absent in the exposed section, and so far as known none 
of the deep wells north of San Diego, except the Clark oil well, have 
encountered conglomerates below sea level. 

Beds belonging to the upper part of the Eocene can be recognized 
in the logs of wells south of Mission Valley, where they underlie later 
Tertiary deposits, but the base of the Eocene has not been recognized 
in these logs. 

The thickness of the Eocene in the vicinity of San Diego and La 
Jolla is stated by Dickerson 2 to be 600 to 700 feet, and paleontologic 
studies of the strata have enabled him to conclude that 

1 Merrill, P. J. H., Geology and mineral resources of San Diego and Imperial counties: California State 
Min. Bur. Repts., 1913-14, 1914. 

2 Dickerson, It. E., Stratigraphy and fauna of the Tejon Eocene of California: California Univ. Dept. 
Geology Bull., vol. 9, No. 17, p. 437, May 2, 1916. 






GEOLOGY. 57 

(1) The Tejon Eocene strata of San Diego County have yielded a fauna of over 
90 forms, many of which are common species in the Tejon of Canada de las Uvas. 
(2) The same faunal stage is present in both localities — that is the Rimella simplex 
zone. (3) Orogenic movements in post-Eocene time have been far less vigorous in 
the vicinity of San Diego than in central California, although equivalent strata occur 
in both places. 1 

MIOCENE AND PLIOCENE SERIES. 
SAN ONOFRE BRECCIA. 

Most of the rocks of later Tertiary age north of Buena Vista Creek 
are essentially like those in the southern part of the area as described 
under San Diego formation (p. 58). The rocks forming the San 
Onofre Hills, however, are entirely different from any other Tertiary 
rocks in the area, for they consist of very coarse breccias or agglom- 
erates, made up almost entirely of angular boulders and slabs of 
garnetiferous glaucophane schists and other schistose rock frag- 
ments. So far as known, none of the materials composing the mass 
were derived from rocks within the area, but rocks of this character 
occur in place in some of the islands off the coast, and it has been 
suggested that probably the material now exposed in the San Onofre 
Hills was derived from the west. These rocks are considered to be of 
early Miocene age and are older than the Tertiary formations which 
surround them. Fairbanks 2 describes their relation to the adjacent 
later formations as follows : 

The Tertiary beds north of the Santa Margarita Creek are very different in outline 
from those south. Instead of their extending in a gradual slope from the older moun- 
tains to the ocean, there arises in them, near their western border, a range of moun- 
tains, known as the San Onofre Mountains. These extend parallel to the ocean at 
an average distance of 2 miles. They rise north of the Santa Margarita Creek and 
extend to the San Onofre Creek. They have a gradual slope on the west, rising to 
an elevation of 1,400 feet, but are quite abrupt on the east. Los Flores Creek cuts 
through the southern end of this range, showing that while the soft, clayey sandstones 
between it and the Santa Margarita Mountains slope only 5° to 10° southwest, the 
rocks of the range itself dip west at an angle of 35° to 40°. The formation is a breccia, 
the fragments of which are argillitic, micaceous, and hornblendic schists. Some of 
these fragments are of great size, one boulder of hornblende schist being 8 feet in 
diameter. Pebbles of white quartz and other hard metamorphics are also present. 
The soft, coarse sandstone in which the fragments are imbedded show no traces of 
any granitic matter. The range was ascended 2 miles north of the Los Flores ranch 
house and found to consist entirely of fragmental schists, such as those mentioned, 
dipping southwest at an angle of 45°. The mountains were also climbed at their 
northern end, near San Onofre Creek. Here there is a very abrupt escarpment on 
the eastern side. The strata dip toward the ocean at a high angle, while the irregular 
hills and ridges of soft light-colored sandstone lying east toward the Santa Margarita 
Mountains are nearly level. After a careful study of the range the conclusion was 
reached that its origin was due to a great fault, represented by the very abrupt eastern 
slope, tilting the elevated portion to the west at a high angle. I believe that this 
fault took place after the deposition of the Tertiary strata. As far as my observation 

1 Dickerson, E,. E., op. cit., p. 440. 

2 Fairbanks, II. W., Geology of San Diego County; also of portions of Orange and San Bernardino coun- 
ties: California State Min. Bur. Eleventh Ann. Kept., p. 98, 1893. 



58 GKOTJND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

went the Tertiary beds on the east do not rise to meet the San Onofre range, as they 
would to a certain extent if it were present when they were deposited; on the contrary, 
they dip toward it. 

SAN DIEGO FORMATION. 

In the south wall of Los Penasquitos Canyon the Eocene rocks are 
overlain by a thin bed of conglomerate that increases in thickness 
southward, becoming separated from the Eocene by increasingly 
numerous lenses of sandstone and sandy shale until in Mission Valley 
the Eocene is overlain by more than 400 feet of these later Tertiary 
deposits. The stratigraphy of these later deposits is exceedingly 
complex. The beds are discontinuous and are generally very limited 
in extent, so that even in the small canyons it is commonly impossible 
to correlate the beds exposed in opposite walls. In many places there 
is exhibited an extremely intimate interbedding of coarse and fine 
material, thin layers of clay or shale separating thick layers of coarse 
conglomerate, and short layers of limestone only a few inches thick 
occurring within coarse sandstone. 

As shown by the accompanying sections (pp. 61-69) the lithology of 
the later Tertiary deposits in this area presents most pronounced 
variations, both horizontally and vertically. The lithologic units 
commonly extend over small areas and either end abruptly with 
entirely different deposits, such as shale and conglomerate, in juxta- 
position, as if the one had been laid down in a trough cut in the 
other, or they change gradually by giving way to increasing admix- 
tures of other material until they appear as entirely different deposits, 
or they gradually diminish in thickness until they disappear. Some 
interesting sections were exposed just east of San Diego by excava- 
tions for the extension of city streets, in which cross sections of sand- 
filled channels in clay were very distinctly shown. Some beds are 
more extensive than others, and a few deposits of conglomerate cover 
comparatively large areas, but on the whole the discontinuity of 
beds is an outstanding characteristic of these deposits. 

The beds are in general less indurated than the underlying Eocene 
beds. Excepting the very rare limestone lenses or concretions, the 
firmest beds are conglomerates, but these owe their firmness largely 
to the clay that fills the spaces between pebbles and boulders and 
serves as an effective cement. Wells have been dug by hand to 
depths of nearly a hundred feet without encountering rocks hard 
enough to require blasting. 

Marl and calcareous material of a chalky appearance are common 
in the deposits. In some places, as, for example, in the vicinity of 
La Mesa, beds of marl several feet thick occur, but this material 
appears most commonly as friable lumps and disseminated particles 
in clay beds. A typical example is exhibited in an exposure along 
the road extending from the end of Sixth Street, San Diego, to 






GEOLOGY. 



59 



Mission Valley (see section of San Diego formation, p. 62), and a 
deposit almost identical with this is exposed in the south wall of 
San Luis Rey River about 1J miles east of Oceanside. In both these 
exposures white lime is present in sufficient amounts to give the beds 
a pronounced gray color. 

The sandy marls which are exposed around Mission Bay and in 
Mission Valley and that underlie the conglomerates east of San Diego 
have been referred to in the literature * as the San Diego beds. 
Fossils collected from these beds have been classified as Pliocene. 

In the following quotation C. R. Orcutt 2 has assembled the data 
in regard to fossil collections obtained from these deposits in a well 
boring in the city of San Diego. 

In the early days of the present city of San Diego, Calif., a well was sunk to a depth 
of 160 feet, at the corner of Ash and Eleventh streets, which for a time formed the 
source of the water supply of the then small town. The depth reached was not far 
from the present sea level, and it may be well to add that the well is situated at the 
mouth of one of the small canyons, opening out upon the lower mesa, upon which 
is built the business portion of our city to-day. 

Mr. Henry Hemphill, the indefatigable student and collector of our west coast 
Mollusca, was then, as now, a resident of San Diego, and present to examine the 
debris as it was brought up from the well. At the depth of about 90 feet a stratum 
of indurated sandstone was passed through, in which was found casts of various shells, 
together with a few well-preserved fossil shells. 

At a greater depth, from 140 to 160 feet, came a rich variety of well-preserved shells, 
imbedded in a usually rather soft matrix, composed of loosely aggregated grains of sand 
or fine sandy mud, occasionally hardened by infiltration of lime-bearing water. 

The following is a list of the species obtained from this well by Mr. Hemphill, as 
they were identified and published in the Proceedings of the California Academy of 
Sciences, vol. 5, pp. 296-299, 1874, by Wm. H. Dall: 



Glottidia albida Hinds. 
Xylotrya sp. indet. (tubes only). 
Cryptomya calif ornica Conrad. 
Dentalium hexagonum Sowerby. 

semipolitum Broderip and Sowerby. 
Solen rosaceus Carpenter. 
Solecurtus calif ornianus Conrad. 
Myurella simplex Carpenter. 
Macoma expansa Carpenter. 
Callista sp. indet. (smooth, thin, and in- 
flated; much like C. newcombiana) . 
Cardium centifilosum Carpenter. 
Venericardia borealis Conrad. 
Lucina nuttallii Conrad. 

borealis Linne. 

tenuisculpta Carpenter. 
Cryptodon flexuosus Montague. 
Modiola recta Conrad. 



Area microdonta Conrad. 

Nucula n. sp. Carpenter (like N. tenuis). 

Acila lyalli Baird (frequently reported as 

A. castrensis Hinds). 
Leda caelata Hinds. 
Pecten hastatus Sowerby. 
Amusium caurinum Gould. 
Janira florida Hinds. 
Ostrea conchaphila Carpenter. 
Placunanomia macroschisma Deshayes. 
Tornatina eximia Baird. 
Cylichna cylindracea Linne. 
Siphonodentalium pusillum? Gabb. 
Calliostoma annulatum Marty n. 
Galerus filosus Gabb. 
Crepidula navicelloides Nuttall. 

princeps Conrad (not C. grandis of 
Middendorf). 



1 Dall, W. H., A table of the North American Tertiary horizons, correlated with one another and with 
those of western Europe, with annotations; U. S. Geol. Survey Eighteenth Ann. Kept., pt. 2, p. 337, 1898. 
* West American Scientist, vol. 6, No. 46, p. 84, August, 1889. 



60 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



Turritella jewettii Carpenter. 
Bittium asperum Carpenter. 
Drillia sp. indet. 

sp. indet. 

sp. indet. 

sp. indet. 
Surcula carpenteriana Gabb. 
Mangilia variegata Carpenter. 

sp. indet. 

sp. indet. 

sp. indet. 

sp. indet. 
Clathurella conradiana Gabb. 
Odostomia straminea Carpenter. 

sp. indet. 
Turbonilla torquata Carpenter. 
Eulima rutila Carpenter. 
Scalaria subcoronata Carpenter. 



Cancellaria sp. indet. 

sp. indet. 

sp. indet. 

sp. indet. 
Neverita reclusiana Petit. 
Sigaretus debilis Gould. 
Ranella mathewsonii Gabb. 
Olivella boetica Carpenter. 
Nassa fossata Gould. 

mendica Gould. 
Astyris tuberosa Carpenter. 

sp. indet. 
Ocinebra lurida Carpenter. 
Pteronotus festivus Hinds. 
Trophon orpheus Gould. 
Fusus (Colus) dupetit-tbouarsi? Kiener. 
Chrysodomus diegoensis Dall, n. sp. 

n. sp. (too imperfect to describe). 



The following additions to the list of species from this well were reported by Dall. 3 



Turritella cooperi Carpenter. 
Turbonilla stylina Carpenter. 



Venericardia monilicosta Gabb. 
Janira dentata Sowerby. 
Cylichna alba Brown. 

Other additions to the list are incorporated by Dall 2 in substantially the*same 
list as was published in the Proceedings of the California Academy of Sciences, which 
I note as follows: 



Mamma nana Moller. 
Cadulus fusiformis. 
Pecten expansus Dall. 



Clementia subdiaphana Carpenter. 
Lucina acutilineata Conrad. 
Nucula exigua Sowerby. 
Volutopsis sp. indet. 

The stratum from which these fossils came is probably at least 70 feet in thickness 
in places, and the bed is of wide extent, as is shown by the fossils which have been 
found in nearly every well that has been sunk in San Diego. 

The beds described by Orcutt are near the base of the later Tertiary 
section. They are best developed in the immediate environs of the 
city of San Diego, but they have been recognized by their lithologic 
character as far south as Otay and in the northern part of the area in 
the vicinity of Oceanside. They seem to be integral parts of a single 
formation and chronologically inseparable from the other lenticular 
strata with which they are interbedded. On this ground it is pro- 
posed to include all the later Tertiary marine deposits in this area 
under the name San Diego formation. 

South of Otay Valley the San Diego formation is probably more 
than 500 feet thick, but between Otay River and Los Penasquitos 
River it is in most places less than 500 feet thick. The principal 
lithologic characteristics which distinguish this formation from the 
underlying Eocene are (1) lenticular bedding and deltoid structures; 
(2) lower degree of induration; (3) absence of limestone beds, but 



i Dall, W. H., U. S. Nat. Mus. Proc, vol. 1, pp. 10-16. 
2 Idem, pp. 26-30. 



GEOLOGY. 



61 



large amounts of calcuim carbonate disseminated through the fine- 
grained deposit; (4) presence of large quantities of coarse material 
as thick beds of conglomerate, as beds of coarse gravel, and as mix- 
tures of sand, gravel, and clay; (5) predominance of sandstones and 
coarser materials over clay. 

The San Diego formation is essentially a shallow-water deposit, as 
is indicated by its deltoid structure and by the presence of fossil 
mud cracks. Most of the materials of which it is formed were 
derived from the highland area on the east, some of them being 
transported only short distances and others being brought from com- 
paratively remote sources. The conglomerates are made up of well- 
rounded pebbles, some of which are derived from rocks that have not 
been found in place in San Diego County; and the presence of the 
large fluviatile deposits east of Foster suggests that some, but prob- 
ably only a small part, of this material may have been transported 
from sources entirely outside the San Diego area. 

The following well log shows the character of the strata on the 
north end of Point Loma, but no fossil evidence of the age of the suc- 
cessive beds was preserved. The surface deposits belong to the San 
Diego formation and the lowest beds may be Cretaceous. 

Table 5. — Log of well on pueblo lot 146, Point Loma, San Diego County, Calif. 

[Begun Aug. 18, 1900; completed Mar. 18, 1901. Authority, Katherine Tingley, owner. Elevation of 
mouth of well, 255.88 feet above high tide.] 





Thick- 
ness. 


Depth. 




Thick- 
ness. 


Depth. 


San Diego formation: 


Feet. 
3 
5 
22 

10 

20 

40 

6 

84 
2 
8 
2 

58 
1 
1 
3 


Feet. 
3 

3 8 

' 40 
GO 
100 
106 

190 
192 
200 
202 
260 
261 
262 
265 


E ocene— Continued . 

Water-bearing sand, good 


Feet. 

6 
27 

2 
20 

1 * 

27 
10 
10 
2 
16 

2 

10 


Feet. 




271 






298 


Water-bearing sand 

Sandy shale and dry sand^ 


Water-bearing sand 


300 
320 


White quartz l^*^. 
Blue granitej ^^ 
Light-blue shale 




Sand 


321 


Eocene: 


323 
350 


Water-bearing sand 


Alternate shale and sand . . 


330 
370 


Water-bearing sand 


Water-bearing sand 


372 
388 




Water-bearing gravel and 




Coal 


390 


"Ore" 


Shale, gravel, and clay — 


400 







Diameter of well, 6 inches, to 40 feet; 5 inches, 40 to 400 feet. Water level, 253 
feet below surface, or 2.88 feet above high tide. Estimated yield, 35,000 gallons daily 
if all water-bearing strata are used. 1 



i U. S. Geol. Survey Bull. 264, p. 79, 1905. 



62 GROUND WATERS OF WESTERN" SAN DIEGO COUNTY, CALIF. 



A well which was being drilled for Mr. L. K. Lanier, in South Las 
Choyas Valley, about 4 miles east of San Diego, penetrated the 

following beds: 

Table 6. — Log of L. K. Lanier's well (0 5). 
[Furnished by Wilkes James, driller. Surface elevation about 175 feet above sea level.] 



Thick- 
ness. 



Depth. 



San Diego formation: 

Yellow sand with a few layers of clay 

Very fine dark-colored sand containing a large admixture of fine black mica; 
quite fluid when wet. Abundant fossils 



Feet. 
210 



150 



Feet. 



210 
360 



W. H. Dall examined a collection of fossils obtained from the lower 
member of this section and classified as upper Miocene or probably 
Pliocene, the following forms: 



Cancellaria sp. 

Olivella pedroana Conrad. 

Tritonalia sp. 

Nassacf. N. mendica Gould. 

Thais cf . T. lamellosa var. 

Neverita cf . N. recluziana. 

Dentalium sp. nov. 

Leda cf. L. area trilineata Conrad. 



Pecten. 2 sp. indet. 
Pliacoides 2 sp. 
Tellina ? sp. 
Dosinia ponderosa. 
Chione sp.? 
Spisula sp. 
Cardium sp. 
Corbula sp. 



The following section is exposed in the south wall of Mission Valley 
2 miles east of North San Diego. 



Feet. 

60 
20 



Section of San Diego formation. 

(At top, elevation, 250 feet above sea level) fine to medium-grained 

sand, containing poorly preserved casts of shells 

Conglomerate 

Coarse sand, containing garnet grains and small flakes of black 
mica, generally white to brown but locally greenish, with irreg- 
ular streaks and masses of marl. At the bottom the sand is 
locally thin bedded and dark colored. This member closely 
resembles the dark sand penetrated by Lanier's well (O 5) at the 
depth of 210 feet, and by the Y. M. C. A. well in San Diego (O 1) 
at the depth of 145 feet. It is presumably the same bed as that 
which yielded the fossils described on page 59 170+ 

Robert Dick's well, just northwest of Hollywood, penetrated the 
San Diego formation to the depth of 203 feet, encountering alter- 
nating beds of clay and conglomerate as follows : 

Table 7. — Log of Robert Dick's well (0 7). 
[Furnished by Wilkes James, driller. Surface elevation about 250 feet above sea level.] 



l Diego formation: 

Clay loam 

Conglomerate 

Clay -. 

Conglomerate 

Clay 

Clay and gravel; water at 
114 feet 



Thick- 
ness. 


Depth. 


Feet. 


Feet. 


40 


40 


3 


43 


9 


52 


7 


59 


31 


90 


35 


125 



San Diego formation— Contd 

Hard conglomerate 

Gravel and clay 

Coarse conglomerate 

Clay and gravel 

Conglomerate 

Clay and gravel 



Thick- 
ness. 



Feet. 



Depth. 



Feet. 



136 
165 
174 
186 
194 



GEOLOGY. 



63 



A well drilled at Angelus Heights to the depth of 375 feet pene- 
trated the following beds : 



Table 8. — Log of the Angelus Heights well (0 8). 
[Authority, Wilkes James, driller. Surface elevation about 400 feet above sea level.; 






Thick- 
ness. 


Depth. 




Thick- 
ness. 


Depth. 


San Diego formation: 

Top, hard yellow clay 

Chalky formation, and 


Feet. 
25 

50 

140 

2 


Feet. 
25 

75 

215 

217 


San Diego formation — Contd. 

Clay and conglomerate 

Water-bearing sand 


Feet. 
93 

(?) 
(?) 
5 


Feet. 

310 
(?) 
370 


Clay and conglomerate 


Sand yielding salty water. 


375 


Sand and gravel yielding 
water 









About 3 J miles east of Chula Vista and 1| miles southeast of 
Bonita the north wall of a small canyon, locally known as Fossil 
Canyon,, exhibits a section of alternating lenticular deposits of sand 
and sandy clay containing large masses of concretionary lime- 
stone and lenticular beds of impure limestone. A collection of fossils, 
which were obtained principally from the limestones which are in 
place at an elevation of about 300 feet above sea level, are considered 
by W. H. Dall to be of upper Miocene age. The following forms 
were identified: 

Cetacean bone. Pecten cf. P. diegensis Dall. 

Cancellaria sp. Mactra albaria Conrad. 

Fasinus sp. Thracia n. sp. 

Turritella sp. Venerid genus undet. 

Two miles east of Chula Vista a tributary to the Sweetwater has 
cut a deep canyon in the mesa formations. Conglomerates are less 
in evidence in the exposures here than north of Sweetwater Kiver. 
About 2 miles east of Chula Vista and 1J miles south of Bonita, near 
the top of the south wall of the canyon, the following section is 

exposed: 

Section of San Diego formation 2 miles east of Chula Vista. 

Feet. 

(Top, elevation about 200 feet above sea level) loose gravel and 

clay 3+ 

Coarse impure sandstone, somewhat calcareous, containing fossil 

mud cracks, some of which are 16 inches deep 3 

Calcareous sandstone containing a few fossils 40 

A collection of fossils from the lowest member was submitted to 
Mr. Dall, who describes it as Eocene (?), like the collection obtained 
in San Clemente Canyon. (See p. 54.) The following genera are 
represented : 



Ostrea. 
Chione. 
Phacoides. 



Psammacema. 
Sanguinolaria. 
Siliqua. 



Mr. Dall has indicated some doubt as to the age of these fossils 
and it is quite possible, considering the close proximity of upper 



64 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Miocene beds, 3| miles east of Chula Vista and 11 miles southeast of 
Bonita (p. 63), that they may be younger than Eocene. If they 
are Eocene there is practically an entire absence of the San Diego 
formation at this locality, and the contact between the Eocene and 
the San Diego is shown to be irregular, the top of the Eocene being 
more than 300 feet higher here than it is in the vicinity of San Diego, 
where, according to notes published in the West American Scientist * 
the later Tertiary deposits here designated San Diego formation 
extend at least to the depth of 110 feet below sea level. The following 
note relates to a well boring made on Coronado Island in 1886: 

In boring for artesian water a stratum of sand was found containing numerous fossil 
shells of the later Tertiaries. The more prevalent species were Phasianella compta, 
Ostrea lurida, and Anomia lampe, in the order named. The stratum was found at a 
depth of nearly 70 feet. 

These species, according to W. A. English, belong to the lower 
Pliocene. 

The following note appears in the issue of the West American 
Scientist for July, 1890 (p. 24). 

When the Coronado Beach Co. was boring an artesian well on Coronado Beach, 
San Diego, in 1886, a fossil tooth was found at a depth of 110 feet which was presented 
by H. L. Story to Mrs. K. S. Eigenmann. This has beenexamined by Prof. E. D. Cope, 
editor of the American Naturalist, who identifies it as a left upper molar of an extinct 
species of horse, Equus excelsus. 

According to J. W. Gidley, of the National Museum, the evidence 
of one tooth is hardly sufficient to distinguish between Equus excelsus 
and Equus occidentalis, but either of these species may occur in the 
Pliocene. 

The following well logs, particularly the logs of the Chula Vista 
Oil Co.'s borings, which, as shown on Plate II, are close together, 
illustrate the variable character of the deposits in this part of the area. 

Table §.—Log of test well No. 1, Chula Vista Oil Co. (0 23). 
[Completed 1901. Surface elevation about 150 feet above sea level. Authority, Mrs. M. J. Herman.] 



San Diego formation: 

Gravel, sand, clay. 

Conglomerate 

White sand 

Conglomerate 

Eocene: 

White sand 

Sandstone 

Blue sand 

Shale 

Water sand 

Shell 

Quicksand 

Shell 

Blue clay and sand . 



Thick- 
ness. 


Depth. 


Feet. 


Feet. 


120 


120 


15 


135 


16 


151 


2 


153 


22 


175 


45 


220 


30 


250 


(?) 


(?) 


(?) 


270 


4 


274 


56 


330 


3 


333 


37 


370 



Eocene— Continued . 

Shell 

Shale 

Shell 

Blue clay, sand. 
Very hard shell. 

Clay 

Shell 

Shale (gas) 

Sand 

Clay 



Clay 

Shell 

Clay (oily particles). 



Thick- 



Feet. 

1 

83 

5 

105 

.23 

13 

1 

11 
12 
28 
8 
9 
1 



Depth. 



Feet. 



371 
454 
459 
564 
587 
600 
601 
612 
624 
652 
660 
669 
670 
678 



West American Scientist, vol. 2, No. 15, p. 32, April, 1886. 






GEOLOGY. 



65 



Table 10.— Log of test well No. 2, Chula Vista Oil Co. (0 24). 
[Completed 1901. Surface elevation about 150 feet above sea level. Authority, Mrs. M. J. Herman.] 





Thick- 
ness. 


Depth. 




Thick- 
ness. 


Depth. 


San Diego formation: 

Surface clay and sand 


Feet. 
116 
14 

13 

1 
18 

1 
33 

2 
42 
15 

2 
30 

2 


Feet. 
116 
130 

143 
144 
162 
163 
196 
198 
240 
255 
257 
287 
289 


Eocene— Continued . 


Feet. 

23 
1 
8 
3 
4 
1 

20 

44 
4 
9 
5 

57 
2 


Feet. 
312 


Shell 


313 




Clay 


321 




Shell 


324 


Shell 


Sand and soft shale 

Shell . 


428 


Clay and sandstone 

Shell 


429 


Sand 


449 




Clay 


493 


Shell 


Shell 


497 


Clay, sandstone, and shale. 


Clay 


506 


Hard shell 


511 


Shell 


Alternate sand and clay. . 
Conglomerate 


568 


Shale 


582 


Shell 











Table 11.— Log of test well No. 3, Chula Vista Oil Co. (O 26). 
[Completed 1992. Surface elevation about 150 feet above sea level. Authority, Mrs. M. J. Herman.] 



San Diego formation: 

Surface soil 

Cemented sand . . 
Conglomerate — 

Clay 

Sandstone 

Clay 

Soft sandstone. . . 

Clay 

Water gravel 



Thick- 
ness. 


Depth. 


Feet. 


Feet. 


12 


12 


10 


22 


22 


44 


54 


98 


12 


110 


30 


140 


30 


170 


5 


175 


35 


210 



Eocene: 

Clay 

Sand 

Clay 

Hard shell 

Shale (oil and gas) 

Clay 

Very hard shell. . . 

Blue clay 

Conglomerate 

Light-yellow shale 



Thick- 
ness. 




Depth. 



Feet. 



280 
310 
400 
402 
420 
450 
453 
626 
645 
660 



Table 12.— Log of test well No. 4, Chula Vista Oil Co. (O 27). 
[Completed in 1902. Surface elevation about 135 feet above sea level. Authority, Mrs. M. J. Herman.] 



San Diego formation: 

Surface soil 

Sand and boulders 

Conglomerate 

Clay 

Sandstone 

Clay 

Sand and boulders 
Eocene: 

Sandstone 

Clay 

Shell 



Thick- 
ness. 


Depth. 


Feet. 


Feet. 


12 


12 


9 


21 


20 


41 


54 


95 


19 


114 


32 


146 


12 


158 


7 


165 


21 


186 


7 


193 



Eocene — Continued . 

Clay 

Sand 

Clay 

Hard shell 

Shale 

Blue clay 

Shell 

Blue clay 

Hardshell 

Blue clay 

Conglomerate — 




Depth. 



Feet. 



271 
304 
390 
401 
416 
447 
449 
512 
515 
619 
643 



115536°— 19— wsp 446- 



G6 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Table 13. — Log of the Chula Vista oil well (0 25). 
[Surface elevation about 150 feet above sea level. Authority, Mrs. M. J. Herman.] 





Thick- 
ness. 


Depth. 




Thick- 
ness. 


Depth. 


San Diego formation: 

Surface sand and clay 


Feet. 
55.6 
25 

38.8 
16.6 
5 

18 
32 

9 
16 

8 

4 
25 
87 
12 

7 
67 

5 

12 
3S 

3 

92.2 
25 
92. 4 

8.4 
26 

3 

3 

12.5 
52.1 

8.2 

4 
13 

9 

8 

4 
16.2 

1 

3.6 

3.4 

? 

? 

? 

? 

? 

8 
10 

10 
32 

? 

? 


Feet. 
55.6 
80.6 
129.4 
146 
151 

169 

201 

210 

226 

234 

238 

263 

350 

362 

369 

436 

441 

453 

491 

494 

586.2 

611.2 

703.6 

712 

738 

761 

764 

776.5 

828.6 

836.8 

840.8 

853.8 

862.8 

870.8 

883.8 

900 

901 

904.6 

908 

? 

? 
925 

? 
940 
948 
958 

968 

1,000 

? 

1,030 


Eocene— Continued. 

Light clay and sand 


Feet. 
30 
10 
36 
20 
24 
5 
? 

? 

1 
40 

1 
12 

8 
40 

? 

? 

5 

25 
23 
17 

? 

? 

5 
22 

? 

? 

? 

? 

? 

? 

? 

? 
97 
28 

4 
28 

3 
11 

2 

? 

? 

? 

6 
17 

2 
100 

2 

9 

4 
35 


Feet. 

1,060 
1,070 
1,106 
1 126 


Clay 


Clay sand and boulders . . 
Clay and sand . . . 


Sand with water 






1 150 




Light clay, sticky 


l'l55 


Sand 




y 


Blue clay and sand 


Coarse gravel and boul- 


1 174 


Blue clay and sand 

Sand 


Hard shell 


1 175 




l' 215 






L216 
1 228 


Sand 


Light clay and sand 

Dark sand 


Blue clay and sand 


1^236 
1 276 






Shale 




' 7 


Blue clay and sand 


White sand 


1,295 
1,300 
1 325 


Shell 




Sand 




Blue clay and sand 


Light clay and sand 


1,348 

1,365 

2 


Blue clay and sand 


White sand 






1 380 


Yellow cla v 




1 385 


White sand 


Light clay 


1,407 


Clay 


White sand 


White sand and clay 


Light clay 


1,440 


Hard shell 




? 


Light clay and sand 


Hard sand 


1 457 


White sand 


? 


Sand 


Hard fine sand 


1,460 


Light clav 


White sand 


? 


White sand 


White clay 


1,475 
1,562 
1,590 
1,594 


Clav 


Blue sand and clay 

Blue clay and sand 

Hard white sand 


Sand 


Clay 




Blue clay and sand 


1,622 
1,625 
1,636 
1,638 
? 


Hardshell 


Hard sand 


Blue clay and sand 

Hard white sand 






Blue clay and sand 




1 


White sand 


Blue clay and sand 

Hard white sand 


1,657 




1,663 
1,680 


Clay and sand 


Blue clay and sand 

Hard white sand 




1,682 
1,762 
1,764 
1,773 
1,777 


Light clay and sand 

Dark clay, sand, and 
gravel 


Dark clay and sand shale. 
Hard white sand 


Dark clay and sand shale. 
Hard white sand 




Clav and sand 


Blue clay and sand shale. . 


1,812 









Casing log of the Chula Vista oil well (O 25). 



Diameter. 


Depth cased. 


Inches. 


Feet. 


16 


0-270 


14 


130-385 


12 


0-1, 115 


1% 


0-1, 346 


SVs 


0-1, 485 


4^ 


0-1, 670 


3^8 a 


0-1, 760 



a Stovepipe lining. 






GEOLOGY. 



67 



Table 14.— Log of the Lo Tengo Oil Co.'s well (0 62). 
[Surface elevation, 375 feet above sea level.] 





Thick- 
ness. 


Depth. 




Thick- 
ness. 


Depth. 


San Diego formation: 


Feet. 
20 

20 

200 
70 

10 
37 
43 
45 
50 
35 
42 

? 

? 
35 
25 

? 

? 
25 
50 

? 

? 

? 
? 

70 


Feet. 
20 
40 

240 
310 

320 
357 
400 
445 
495 
530 
572 

? 
605 
640 
665 

? 
720 
745 
795 

? 

860 

? 

1,365 
1,435 


Eocene— Continued . 

Brown shale 


Feet. 
15 
37 
15 
38 
90 
50 
38 

? 

? 

185 

472 

40 

127 

18 

200 

32 

16 

17 

? 

? 

? 

? 

? 
50 

? 

? 


Feet. 
1,450 




Sand and conglomerate. . . 
Brown shale 


1,487 


Soft light yellow sand, 


1,502 
1,540 
1,630 


Sand, and conglomerate. . . 

Dark soft shale, water 

Brown shale, sand 

Sticky blue clay 




Eocene: 


1,680 
1,718 




Blue shale 


? 




Red sand 


1,758 
1,943 
2,415 
2,455 
2,582 
2,600 




Blue clay, streaks of sand. 

Hard calcareous rock 

Hard fine sand 


Soft sand and blue shale . . 


Yellow sand, water at top . 


Calcareous sand rock 

Dark sand rock 




Calcareous rock 


2,800 
2,832 
2,848 
2,865 
? 


Gray sand shell, gray sand 


Conglomerate and sand. . . 
Conglomerate 


Water 


Sand, gas 




Gas and oil 




Soft sand 


2,965 


Sandy shale 


Hard calcareous sand 

Oil 


? 




? 




Soft sand, oil 


2,985 

3,035 

? 


Light brown shale, hard 


Sand 


Soft sand, oil 


Brown shale and shells . . . 
Black sand, water 


Hard, calcareous ro k, 
streaks of sand in lower 


3,400 







Table 15. — Log of the Tia Juana oil well (O 63). 
[Authority, Capt. J. F. Scott. Surface elevation, about 85 feet above sea level.] 





Thick- 
ness. 


Depth. 




Thick- 
ness. 


Depth. 


San Diego formation: 


Feet. 
80 
2 

500 

? 

? 

4 
96 


Feet. 

80 
82 

582 

582 

800 
804 
900 


Eocene — Continued. 

Shale and sand alternating 

Shale with streaks of oil 

sand 


Feet. 
100 

8 

92 

1 

249 

12 

43 


Feet. 
1,000 
1,008 


Water sand 


San Diego (?) formation: 


Quicksand with mica 

Eocene: 

Coal seam, thin 


Alternating hard and soft 

sand and blue clay 

Hard fossil bed 


1,100 
1,101 
1,350 


Shale and sand alternat- 


Sandstone with water b... 

Hard sand, trace of oil 

Sands and black shales, 
showing oil 


1,362 


Shale with trace of oil 

Hard sand 


1,405 









a From a depth of 800 feet the sand bucket brought to the surface a specimen oiSpicula sp.? (crushed) 
Miocene? 

b Water encountered at 1,125 feet below surface; rose nearly to surface but leaked into higher formations; 
water of excellent quality. 

POWAY CONGLOMERATE. 

The rocks forming Poway Mesa are chiefly conglomerates, but 
lenses of cross-bedded sand and thin layers of marly clay are exposed 
in some of the canyon walls. Large deposits of similar materials 
occur in a narrow belt that extends from Poway Mesa eastward to 
Witch Creek, as shown on Plate III. They are also well exposed 
near the town of Poway and form the south wall of Poway Valley. 
The maximum thickness of the conglomerates west of Foster is about 
1,000 feet. Two hypotheses have been advanced to account for the 
occurrence of these deposits. According to one of them, an arm of 



68 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

the sea extended from Foster eastward, in which coarse detritus from 
the surrounding land mass accumulated; the other, proposed by 
Fairbanks (see p. 40), suggests a fluviatile origin of the deposits. 
The following well log exhibits a section of Poway Mesa. 

Table 16. — Log of the Beaver oil well (K 22). 
[Authority, F. C. Tower. Surface elevation, 975 feet above sea level.] 



Thick- 
ness. 



Depth. 



Poway conglomerate: 

Coarse gravels 

Crystalline complex: 

Granitic rock with thin covering of marl. 



Feet. 

875 



175 



Feet. 

875 



1,050 



Note.— Encountered water at 525 feet below surface which rose 100 feet in the casing. Said to be "soda 
water" and strongly mineralized. 

No fossils were found in this formation, and its contact with the 
marine San Diego formation does not afford a definite interpretation 
of its relative age. But the materials of which it is composed, being 
practically the same as the coarser phases of the San Diego forma- 
tion, suggest an age corresponding in a general way with that forma- 
tion. Probably it is somewhat older than the upper part of the San 
Diego, since it is at a much higher elevation and must have emerged 
before the San Diego was raised above the sea, but it may correspond 
in age with the lower part of that formation. 

LATE TERTIARY BEACH DEPOSITS. 

The surface of Linda Vista Mesa is crossed by narrow bands of 
sandstone that represent ancient beach ridges. In most places the 
sandstone is brick-red, but it is locally mottled red and yellow, and 
near Mission Valley is gray. The texture of the rock is variable, 
ranging from very coarse to medium fine, and shows stratification 
only near the surface, where it is most indurated. In a few places 
fossil sun cracks were found in impure facies of the rock. The 
thickness of these deposits ranges from a few feet, south of Mission 
Valley, to 50 feet or more north of Los Penasquitos Canyon (see 
p. 30). They rest on the San Diego formation where these beds 
underlie the surface but continuing northward they rest on Eocene. 

QUATERNARY SYSTEM. 

Two types of Quaternary deposits, distinguished primarily by their 
geologic occurrence, are recognized in this region — the marine 
Pleistocene and the nonmarine Pleistocene and Recent valley fill. 
The marine Pleistocene occurs principally along the coast, resting 
unconformably on older formations, but the valley fill occupies the 
valleys of the principal streams in all parts of the region, and als 
forms the present floors of San Felipe Valley and Warners Valley. 



• 



GEOLOGY. 69 



PLEISTOCENE SERIES. 
SAN PEDRO FORMATION. 



Littoral deposits of fossiliferous sand and loam occur as a veneer 
on the older rocks in a narrow belt along the shore from San Onofre 
to the boundary (PI. III). North of Soledad Canyon the terraces 
along the shore are surmounted by ridges of semi-indurated sand 
containing Pleistocene fossils, which reach elevations of about 100 
feet, and Pleistocene fossils are distributed over the flat surfaces of 
the benches on which Oceanside, South Oceanside, and Carl are situ- 
ated, as much as a mile inland from the present shore line. 

Fossils collected in the NE. \ sec. 36, T. 11 S. ; R. 5 W., at an ele- 
vation of about 70 feet above sea level include, according to Mr. Dall, 
the following Pleistocene species : 



Neverita recluziana var. alta Dall. 
Pecten circularis Sowerby. 
Chione gnidia Sowerby. 



Chione fluctifraga Sowerby. 
Chione neglecta Sowerby. 



About a half mile southeast of this locality, on the south side of 
the salt marsh at the mouth of Buena Vista Creek, in the SW. \ 
sec. 31, T. 11 S., R. 4 W., a narrow band of black loam on the steep 
terrace slope 50 feet above sea level, contained numerous specimens 
of Neverita recluziana var. alta Dall. 

The following species were identified in a collection of fossils 
obtained from an old beach ridge at the top of the cliffs 2 miles 
north of Delmar (see section, member a, p. 53) : 



Neverita recluziana var. alta Dall. 
Pecten circularis Sowerby. 
Chama mexicana Carpenter. 



Tivela crassatelloides Conrad. 
Chione gnidia Sowerby. 
Chione neglecta Sowerby. 



Small isolated deposits of Pleistocene sand and loam were found 
along Buena Vista Creek as far east as El Salto. Half a mile west 
of El Salto a collection was obtained from a small deposit of dark 
loam among which were the following Pleistocene forms : 



Chione gnidia Sowerby. 
Chione fluctifraga Sowerby. 
Chione neglecta Sowerby. 



Ostrea conchaphila Carpenter. 
Anomia sp. 

Pecten circularis Sowerby. 
Donax laevigata Deshayes. 

Such deposits are common along the shores of all the lagoons as 
far south as Soledad Canyon. 

Pleistocene deposits occur on the shores of Bay and of San Diego 
Bay, as shown on Plate III, generally at elevations between 15 
and 50 feet above sea level. A careful search failed to discover 
Pleistocene fossils between Mission Valley and Tia Juana Valley at a 
higher elevation than 50 feet, but south of Tia Juana Valley the high 
terraces along the shore reaching 100 feet in elevation are thickly 
strewn with Pleistocene shells. 



70 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Arnold * has described the beds in the vicinity of San Diego, and 
has correlated the Pleistocene deposits there with the San Pedro 
formation of Los Angeles County. 

During the field work in connection with this investigation the 
Pleistocene beds near San Diego could not be distinguished from the 
other marine- Pleistocene deposits along the coast in this county, so 
that in accordance with Arnold's correlation, all the marine Pleisto- 
cene in San Diego County has been mapped as San Pedro formation. 

PALA CONGLOMERATE. 

Valley fill of a type not common in this area occurs in the valley 
of the San Luis Key, in the vicinity of Pala. This material is a con- 
glomeritic mass of boulders and residuum, having a thickness of 
about 200 feet above and extending to an undetermined depth below 
the present level of the river. The boulders which make up a large 
part of this formation are all regular, most of them being prismatic 
blocks with slightly rounded corners showing that they have been 
transported only short distances. (See PL XIV, A.) The boulders 
are granite, and the country rock in the immediate vicinity of Pala is 
gabbro, but this gabbro is surrounded by granites, and the degree of 
corrosion exhibited by the boulders seems not inconsistent with the 
assumption that they were derived from granite masses within the 
drainage basin of the San Luis Key. 

This deposit is older than the valley fill which underlies the present 
valley floors, and it may be as old or even older than the San Pedro 
formation, but it has not been possible to ascertain definitely the 
relative ages of these formations. 

LACUSTRINE DEPOSITS. 

The lake deposits of Warners Valley are not exposed in section, 
and information as to the stratigraphic character of the deposits 
over the inner parts of the valley has not been obtained. The 
materials at the surface consist of sandy alluvium. It is probable 
that the sediments in Warners Valley are similar to those in San 
Felipe Valley, where wells drilled near the middle of the valley, to 
depths ranging from 90 to 280 feet, penetrated alternating beds of 
alluvial rock debris, sand, and clay, and ended in a bed of coarse 
rounded boulders. The deposits which form beach ridges and deltas 
around the margins of Warners Valley consist of gravel and coarse 
sand, generally poorly assorted and locally mixed and cemented 
with clay. 

1 Arnold, Ralph, The paleontology and stratigraphy of the marine Pliocene and Pleistocene of San Pedro, 
Calif.: California Acad. Sci. Mem., vol. 3, p. 57, 1903. 






GEOLOGY. 71 

RECENT SERIES. 
VALLEY FILL. 

The most recent geologic formation is the alluvium which occupies 
the valleys of all the principal streams. These valleys were excavated 
during a period in which the land stood possibly 800 or 1,000 feet 
higher than it does at present/ and the streams were able to cut their 
valleys to a depth between 100 and 200 feet below the levels of the 
present valley floors before the beginning of the submergence that 
obliged the streams to aggrade their valleys. The alluvium is 
composed of sand, clay, and gravel derived from the drainage basins 
of the streams. The areal distribution of the valley fill is shown on 
Plate III. The beds of the ancient channels underlying the alluvium 
are generally characterized by coarse boulder deposits. Overlying 
the boulders are alternate layers of gravel, sand, and clay, sand being 
predominant, especially at the surface. 

These deposits comprise the principal ground-water reservoirs in 
the county. They are more fully described on pages 111-121. 

RESIDUUM. 

Most of the igneous rocks in San Diego County are coarse granites 
that yield readily to weathering. In the broad areas in which rocks 
of this kind occur the surface is immediately underlain by residuum, 
or disintegrated granite, in which the joint planes of the original rock 
are still preserved. Disintegration is most advanced at the surface, 
where the rock has been completely reduced to soil, and it decreases 
downward to the solid granite at depths ranging from a few inches 
to about 100 feet. Near the margins of valleys the residuum is covered 
by talus and alluvium washed from the slopes, and in some of the 
valleys alluvium has been spread over the entire valley floors. 

IGNEOUS AND METAMORPHIC ROCKS. 

Only a superficial study of the lithology of the region of crystalline 
rooks has been made in connection with this investigation, so that 
merely a general discussion of the character and distribution of these 
rocks is possible in this report. A large amount of specific and detailed 
information on this subject is, however, contained in the publications 
of the California State Mining Bureau, the most comprehensive paper 
being a report by H. W. Fairbanks 2 on the geology of San Diego 
County and portions of Orange and San Bernardino counties. 

The rooks composing the crystalline complex include both igneous 
and metamorphosed sedimentary rocks of great age, together with 

1 Merrill, F. J. H., Geology and mineral resources of San Diego and Imperial counties, Calif.: California 
State Min. Bur. Bien. Rept., 1913-14, p. 11, 1914. 

2 California State Min. Bur. Eleventh Ann. Hept., p. 76, 1893. 



72 GKOUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIE. 

numerous dike and vein rocks of somewhat more recent origin, and 
consist of gneisses, crystalline schists, quartzites, slates, and lime- 
stone, which have been intruded by granites, which in turn have been 
intruded by diorites and gabbros. The oldest formations occur 
particularly in a belt along the west side of the crest of the Peninsular 
Range, although isolated bodies are present in other parts of the area. 

The igneous rocks include many holocrystalline varieties, together 
with porphyries, f elsites, and amorphous lavas. Coarse granites, cut 
by dikes of fine-grained granite, are by far the most widely distributed 
and constitute the major portion of the crystalline complex. The 
coarser granites, both on the elevated plateaus and on the low valley 
plains, are deeply disintegrated and in many places completely 
reduced to a residual soil. Large masses of basic rocks, including 
gabbro and diorite, are intruded into the granites and metamorphic 
rocks in the eastern part of the area, and of these Cuyamaca Peak, 
Middle Peak, and North Peak, and several of the mountains in the 
vicinity of Pala are composed. The range along the western edge of 
the crystalline area, including Otay, San Miguel, and Cowles moun- 
tains and other lower hills, is composed of felsites and porphyries 
which are shown on the geologic map of the United States 1 as 
effusives of Tertiary or later age. 

A description of these rocks together with a comment on their 
probable age is given by Merrill 2 as follows: 

On the southwestern flank of the granites is a volcanic area, a few miles wide, extend- 
ing northwest some 40 miles from the Mexican boundary and often erroneously called 
"the porphyry dike." This is largely overlain by the Tertiary formations. The 
principal rocks exposed are felsite, quarried for crushed stone at Spring Valley and 
Sweetwater dam. With these, at various points, are tufas and volcanic conglomerates. 
The age of these volcanics is as yet somewhat indeterminate, but the specimen from 
Lo Tengo oil well, of black shale cut by felsite, suggests a post- Jurassic age for the 
latter. 

The felsites may belong to the same period of eruption as the volcanics of Coyote 
Mountain in Imperial County, which underlie the Miocene clays, but they are of 
different type, for the Coyote Mountain effusive rocks are basic and, though they are 
badly decayed and difficult to identify, were probably mostly andesites. 

Fairbanks states that this rock "is without doubt an ancient 
intrusive, very greatly altered. * * * None of the other 
crystalline rocks in San Diego County appear so old or show so much 
alteration." 

Samples were collected by the writer at three localities in the range, 
one in the SW. J sec. 34, T. 17 S., R. 1 E.; one in the NE. \ sec. 4, 
T. 18 S., R. IE.; and one just north of the north boundary of the San 
Dieguito grant, at the center of sec. 16, T. 13 S., H. 3 W. These 

i Willis, Bailey, and Stose, G. W., Geologic map of North America, U. S. Geol. Survey, 1911. 
2 Merrill, F.J. H., Geology and mineral resources of San Diego and Imperial counties; California State 
Hin. Bur. Bien. Kept., 1913-14, p. 11, 1914. 



GEOLOGY. 73 

rocks were examined and described by E. S. Larsen, of the United 
States Geological Survey, as quartz latites, greenish or grayish rocks 
which carry a moderate number of phenocrysts of oligoclase-andesine 
feldspar and a few of chloritized biotite in a very fine, indistinctly 
granular groundmass made up of quartz and orthoclase. The rocks 
are much altered flow breccias, secondary chlorite and calcite being 
abundant, and they carry many included fragments of andesitic and 
latitic rocks. The sample from sec. 16, T. 13 S., R. 3 W., contains 
phenocrysts of quartz and the groundmass is coarser. A sample 
collected by G. A. Waring from Morro Hill is described as a dense, 
aphanitic light-gray andesite or quartz latite. Small laths of 
andesine make up about half of the rock, and augite and magnetite 
are in small amount. The groundmass is glassy, and the rock is 
much less metamorphosed than the rocks described above, being 
possibly of later origin. 

Probably the latest igneous rocks in the San Diego area are the 
lavas, described by Fairbanks, that cap sandstone hills in the extreme 
northern part of the county north of De Luz. 

In an area of crystalline rocks of this character the order in which 
the different rocks were formed is indicated by the phenomena of 
intrusion, and the amount of weathering which the different rocks 
have undergone is a criterion of their ages, but since this is dependent 
as much on rock composition and structure as on the length of time 
that the rocks have been exposed, it is often unreliable as an indication 
of age. But neither of these criteria is in itself sufficient to define 
the geologic age of rocks, and in this area few other data bearing on 
the problem have been obtained. Fossils of Carboniferous age have 
been reported from metamorphic rocks correlative with those in the 
San Diego area, indicating that most of the crystalline rocks are post- 
Carboniferous, and Merrill suggested (see p. 72) a post-Jurassic age 
for the felsites on the west, which, so far as has been determined, are 
not considerably younger than the mass of crystallines. Conditions 
along the contact between the exposed Tertiary sediments and the 
crystallines indicate that the latter were old before the Tertiary 
deposits were laid down and are probably not younger than early 
Cretaceous. Fairbanks states that "although none but Carbonif- 
erous fossils have yet been found, it is probable that the metamorphic 
series contains rocks much older as well as younger," and that he 
believes " that the great convulsion which upheaved and metamor- 
phosed the older rocks and intruded granite into them took place, as 
it did in central and northern California, between the Cretaceous and 
the Jurassic." 



Y4 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

GEOLOGIC HISTORY. 

PRE-CRETACEOUS SEDIMENTATION. 

The early geologic history of western San Diego County is obscure, 
owing to the absence in the eastern part of recognizable time markers, 
and in the western part to the great thickness of the deposits beneath 
which the old formations are buried. The oldest rocks are in the 
eastern part of the region. No fossils have as yet been discovered in 
them, but they have been provisionally 1 correlated with the rocks 
of the Calaveras group, which are believed to be of Carboniferous age. 
In San Diego County these rocks include metamorphosed shales and 
sandstones and, in adjacent areas to the east, limestones. When 
these rocks were deposited, presumably during Carboniferous time 
at the latest, the region was covered by the sea. The materials of 
which the shales and sandstones were composed were probably 
derived from land not far to the east, and they were deposited in 
thick beds that probably extended over all the highland area. The 
rocks on which they were laid down may have been crystallines or 
ancient sediments which have been so thoroughly altered that they 
can not now be recognized as such. 

PRE-CRETAOEOUS OR EARLY CRETACEOUS DIASTROPHISM, VOLCANISM, 

AND METAMORPHISM. 

Late in the Jurassic period or early in the Cretaceous period there 
was a time in which great geologic changes occurred. Many of the 
separate events were no doubt closely related, and some entirely oblit- 
erated the results of earlier action, so that the true sequence of events 
is hard to determine. Into the sedimentary formations great igneous 
masses were intruded, eventually forming the granite rock that under- 
lies practically the whole region. This intrusion elevated the region, 
particularly the highland area, and crumpled and folded the rocks 
into* anticlines and synclines. The sediments were changed by heat 
and pressure to schists, slates, quartzites, and marbles. Erosion of 
the land mass then began and became more vigorous as elevation 
progressed. As a culmination of the processes of volcanism great 
masses of basic magmas were intruded into the granites and overlying 
rocks. These basic masses produced the Cuyamaca peaks and other 
peaks in the eastern part of the area and possibly the porphyritic 
rocks along the western border. 

CRETACEOUS (?) PENEPLANATION. 

Erosion continued until the region was reduced practically to a base 
level. The metamorphosed sediments were in large part removed 

» Merrill, F. J. H., Geology and mineral resources of San Diego and Imperial counties, Calif.: California 
State Min. Bur. Bien. Rept. 1913-14, p. 24, 1914. 



geology. YS 

from the elevated positions and were left only in the protected syn- 
clines, and the ridges and peaks of hard basic rocks were etched into 
relief by the removal of the softer materials into which they had been 
intruded. The debris stripped from the highland area was carried 
into the ocean, where it accumulated in stratified deposits now cov- 
ered by younger sediments. It is probable that during the Creta- 
ceous as well as the Tertiary period the shore line remained essentially 
in the same position — along the boundary between the present coastal 
section and the highland area. In fact it is presumable that a great 
fault line extended along the west edge of the present highland area, 
approximately coincident with that ancient shore line, and that the 
area of sedimentation west of the fault gradually subsided as the 
sediments accumulated, so that thousands of feet of sedimentary 
rocks were laid down at the very edge of the land mass. 

EARLY TERTIARY UPLIFT, REJUVENATED EROSION, AND COASTAL 

SEDIMENTATION . 

A period of uplift and mountain building followed the base-leveling, 
probably in early Tertiary time. 1 During this period the previously 
formed peneplain was in part broken up and high mountains were 
formed along the eastern border of the area. Streams readjusted 
themselves to new topographic conditions and began to carve the 
present drainage lines. A period of intermittent submergence fol- 
lowed, during which Tertiary sediments accumulated along the 
coast. 

LATE TERTIARY AND QUATERNARY EMERGENCE AND OSCILLATION. 

Toward the end of the Pliocene epoch the land movements were 
reversed and the sea slowly withdrew from the present coastal region, 
the periods of quiescence and relatively rapid emergence of the land 
being recorded by well-defined terraces separating successive wave- 
cut plains. 

Oscillatory movements, or alternate elevations and depression of 
the land, characterized the succeeding Quaternary period. During 
an epoch of depression the west edge of the coastal region was sub- 
merged and received deposits of Pleistocene age. During a subse- 
quent epoch of elevation these* deposits were lifted high above the 
sea, and most of the deposits which had been laid down in the larger 
valleys were carried into the sea again by river erosion. The land 
was raised probably as much as 200 feet higher than it stands at 
present, and the principal streams excavated deep valleys. A still 
later subsidence of the land brought about a refilling of all these 
channels to the present levels of the valley floors. 

1 See Fairbanks, H. W., Oscillations of the coast of California during the Pliocene and Pleistocene: Am. 
Geologist, vol. 20, pp. 213-245. 



76 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

These movements are believed to represent the principal events in 
the history of the region, but minor changes of which little or no 
record is preserved have no doubt been constantly taking place. The 
terraces along the coast show that the oscillations of the land have 
continued to the present time, and that changes of geologic impor- 
tance, due in part to land movements and in part to the processes of 
degradation and aggradation, are now in progress. 

PRECIPITATION. 

By C. H. Lee. 
GENERAL CONDITIONS. 

Both the surface and the ground waters of San Diego County 
are derived from precipitation on the surrounding slopes. Of the 
water that falls as rain or snow on any area a part is immediately 
lost by evaporation; another part is directly absorbed by the soil 
or other porous material and percolates downward, and if it escapes 
evaporation from the soil or transpiration from plants this part 
may ultimately reach the water table and join the permanent body 
of ground water; the remaining part collects in stream channels and 
is either absorbed by the porous alluvial debris of the beds, and 
thus joins the permanent body of ground water, or flows onward 
to the ocean. 

Determination of the source and quantity of the ground waters 
of San Diego County requires a knowledge of the quantity and 
distribution of precipitation from season to season and from year 
to year. A wealth of such information is available in the form of 
records of the daily, monthly, and annual precipitation at a great 
number of stations well distributed throughout both the mountainous 
parts of the county and the coastal region. The writer knows of 
no mountainous areas of equal size in the western United States 
for which records of precipitation are so full or so widely distributed. 

CHARACTER OP STORMS. 

Most of the precipitation that occurs in San Diego County is 
due to the great cyclonic storm areas, or "lows," from the north 
Pacific Ocean that appear off the cpasts of southeastern Alaska, 
British Columbia, and northern United States. These lows, which 
are from 500 to 1,000 miles in diameter, have a general easterly 
movement as they reach the continent, but many are deflected 
southward. The frequency and intensity of these storms is greatest 
during the rainy season. Whether the rainy season is what is known 
locally as "wet" or "dry", depends upon the number of "lows" that 
are deflected to the south and the degree of deflection. If the 
percentage of "lows" deflected southward is large the season is wet; 



PKECIPITATION. 77 

in a dry season few or no "lows" reach far enough south to affect pre- 
cipitation in San Diego County. The variation of rainfall from 
month to month during the year and also from year to year is thus 
largely controlled by the general movement of these great Pacific 
storms. Mr. Ford A. Carpenter, for many years stationed at San 
Diego as local forecaster of the United States Weather Bureau, 
states that 90 per cent of the rain falling in the vicinity of San Diego 
results from these storms. 1 It is stated by McAdie 2 and also by 
Carpenter that not one- tenth of the north Pacific "lows" have any 
appreciable effect on the climate of San Diego. 

Another type of storm that occasionally brings precipitation 
during the rainy season approaches the San Diego Coast from the 
southwest. These storms do not move rapidly and many of them 
remain stationary over southern California and Arizona for several 
days. In some winters none of these storms appear and seldom more 
than two yield precipitation over San Diego County. 

Besides storms of these two types, local thunder showers occur in 
the higher mountains of eastern San Diego County during the summer 
months, chiefly July and August. Such storms seldom reach the 
coast, and precipitation in the mountains is usually limited to a few 
hours in the afternoon. Their influence on the total annual precipita- 
tion at mountain stations is small. Stream flow is seldom affected 
by them. 

A fourth type of local storm is the "sonora," which reverses the 
ordinary storm movement and, traversing the country from Sonora, 
Mexico, is heralded by northerly and northeasterly winds. This 
storm is cyclonic in character and extends over large areas. It occurs 
during the summer — May to September — but is very infrequent, 
and precipitation due to it is confined to the mountains and interior 
regions. It has little influence on monthly or annual variations in 
precipitation in San Diego County and seldom causes run-off. 

Precipitation in San Diego County is mainly in the form of rain, 
although more or less snow falls every winter on the higher mountain 
slopes and occasionally at lower levels. Snow remains but a few days 
except in the most protected parts of the highest mountains. 

OBSERVATIONS OF PRECIPITATION. 

Kecords of precipitation are available for periods varying from 
one year to 65 years at 106 stations in San Diego County. Seventeen 
per cent of the records have been kept by the United States Weather 
Bureau, 32 per cent by the City of San Diego, 40 per cent by water 
companies and other organizations, and 11 per cent by private 
individuals. These stations are well distributed over the county, 

1 Carpenter, F. A., The climate and weather of San Diego, Calif., 1913. 

2 McAdie, A. G., Climatology of California: U. S. Weather Bureau Bull. L, 1903. 



78 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

both vertically and longitudinally. Six per cent are more than 5,000 
feet above sea level, 9 per cent are between 4,000 and 5,000 feet, 
16 per cent are between 3,000 and 4,000 feet, 22 per cent are between 
2,000 and 3,000 feet, 11 per cent are between 1,000 and 2,000 feet, 
and 39 per cent are less than 1,000 feet. Horizontally, there is an 
average of one station to about 30 square miles, although the more 
important run-off areas, such as the upper parts of the drainage 
areas of San Luis Rey and Santa Ysabel rivers, have two or more 
stations to the township. The United States Weather Bureau records 
presented in this report were obtained from the printed reports of the 
bureau. Other records were compiled by the writer from the original 
sources or from reliable secondary sources. So far as possible, each 
precipitation gage and its exposure was examined, and the character 
and methods of the observer and the probable accuracy of the record 
were ascertained from personal interview. Practically all observa- 
tions have been made with the standard 8-inch gage in general use 
by the United States Weather Bureau. The writer believes that all 
private records presented in this report have been carefully and 
conscientiously kept and that the results are reasonably accurate and 
within the limits of error of carefully kept precipitation observations. 
The officers of private companies and individuals who had kept records 
were found ready to assist in every way possible in furnishing the 
original records and other information. 

A summary of precipitation observations is presented in Table 17, 
which gives the map number, location, and elevation of the station, 
the authority for and period covered by the record, the average 
observed annual precipitation, and the corrected long-term average 
annual precipitation. The details of the records, in the form of 
monthly and annual depth of precipitation in inches, will be found 
in Table 64 of this report (pp. 290-313). 



PRECIPITATION. 



79 



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80 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 






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115536°— 19— wsp 446 6 



82 GKOUND WATEKS OF WESTERN SAN DIEGO COUNTY, CALIF. 

The precipitation year has been considered as extending from 
July 1 to June 30, so as to cover the rainy season and the period of 
run-off resulting therefrom. The location of all stations is shown on 
Plate XV (in pocket). 

The records published by the United States Weather Bureau 
cover long periods and are among the most valuable available. 
Most of the stations at which observations were made by the 
city of San Diego were installed in 1914 and maintained under 
the direction of Mr. H. A. Whitney, hydraulic engineer, depart- 
ment of water, city of San Diego. Among the records kept 



50 

>- 

5 40 

g 



£ * 







































































































\ 
























\ 


























\ 
























\ 






65 


-year 


averai 


;e=969 


inches 










X 


\ 
























\ 


























\ 


o 

























































































2 4 6 8 10 12 14 16 18 20 ZZ ZA 

PER CENT VARIATION FROM 65-YEAR AVERAGE 

Figure 3.— Relation of length of record of precipitation to variation from the 
average at San Diego, Calif. 

by water companies, 80 per cent were furnished by the Volcan 
Land & Water Co. and the Cuyamaca Water Co., and great 
credit is due Mr. W. S. Post, chief engineer for both companies, 
for the thoroughness and care with which the data have been 
obtained and compiled, as well as to the companies for the 
public spirit displayed in making the records available. Most of 
these gages were installed in 1911, although several stations have 
been maintained by the Cuyamaca Water Co. since 1899. Other 
companies maintaining precipitation stations, to whom credit is due 
for furnishing records, are the Sweetwater Water Co., the Escondido 



PRECIPITATION. 



83 



8 



Mutual Water Co., and the San Diego & Southeastern Railway Co. A 
number of valuable records were also furnished by private individuals, 
some of them covering considerable periods. These individuals are 
too numerous to be mentioned by name, but the writer wishes to 
express his appreciation of their scientific interest in this subject and 
their public spirit in making the records available for publication. 

By summarizing the data obtained at the stations listed in Table 
17 according to the number of complete seasons of record available, 
it appears that 8 per cent of the records are over 25 years long, 2 per 
cent are from 25 to 20 years, 9 per cent are from 20 to 15 years, 7 
per cent are from 15 to 10 years, 10 per cent are from 10 to 5 years, 
50 per cent are less than 5 years, and 27 per cent are less than 3 years 
in length. As precipitation in 
San Diego County is notoriously 
subject to wide annual varia- 
tions, large deviations from the 
mean, sometimes extending 
over several years, it is appar- 
ent that the true averages for 
the depth of annual precipita- 
tion could not be determined 
at many of the stations by 
simply averaging the observed 
quantities. In order to deter- 
mine to some extent the short- 
term records the following pro- 
cedure was followed: The 
whole period of record at San 
Diego was divided into periods 
of 3, 5, 10, 15, 20, 25, 30, 35, 
40, 45, 50, 55, and 60 years each, and the average annual precip- 
itation was computed for each of these periods. The relation, 
in percentage, of the average annual precipitation during each of the 
short periods to the average annual precipitation for the whole 65- 
year period was next computed, and the results were averaged for 
periods of equal length. The results thus obtained were represented 
diagrammatically on figure 3, and a smooth curve was drawn to fit 
the points. 

Inspection of this curve shows that the average of 25-year periods 
differs by 4.6 percent from the 65-year period. Similarly, for Es- 
condido, it was found that the average of the 25-year records differs 
but 3 per cent from the 40-year period. 

There are nine stations in the county at which records are available 
for 25 years or more. These stations are well distributed, both verti- 
cally and geographically (PL XV) , and are as follows : San Diego, at 
which the record covers 65 years; Escondido, 40 years; Valley Center, 



















\ 
















\ 


o 


40- 


year a 


/era^€ 


= 15.51 


inches 






\ 
















\ 


s. 
















\ 


















\ 


V 






































o 



2 4 6 8 10 12 14 16 

PER CENT VARIATION FROM 40-YEAR AVERAGE 

Figure 4.— Relation of length of record of precipitation 
to variation from the average at Escondido, Calif. 



84 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



30 years; Julian, 29 years; Fallbrook, Cuyamaca, and Sweetwater, 
each 27 years; and Campo, 25 years. These stations are termed 
" control stations" in this report because of their use in evaluating 
the short-term records. 

Examination of the annual variations from the normal at the nine 
control stations, as tabulated by percentages in Table 18, indicates 
a general concordance in the variations at the different stations, 
which is due, at least in part, to the fact that most of the precipita- 
tion results from general storms that at any given time cover areas 
many times greater than San Diego County. This condition is well 
known to the inhabitants of San Diego County and other parts of 
southern California, as is shown by the popular terms "wet," "dry," 
and "average," as applied uniformly throughout the region to 
specific rainfall seasons. 

Table 18. — Precipitation index and annual variation of precipitation at nine control 
stations in San Diego County, expressed as per cent of average of observed precipita- 
tion. 



Year (July 1 to 
June 30). 


Julian 
(2S).« 


E scon- 
dido 
(30).a 


Valley 
Center 
(38).a 


Fall- 
brook 
(57).« 


Cuya- 
maca 
(29).o 


Poway 
(35).o 


San 
Diego 
(39).o 


Sweet- 
water 
(36).« 


Campo 
(48).« 


Average 
all control 
stations. 


1872-1873 






59 

191 

67 

98 

45 

134 

43 

124 

81 

84 

60 

258 

68 

155 

69 

116 

134 

154 

135 

91 

104 

50 

125 

61 

122 

55 

59 








67 
174 

59 
104 

39 
166 

82 
148 
100 

98 

51 
268 

90 
175 

86 
101 
114 
155 
108 

90 

96 

51 
123 

64 
122 

52 

54 

62 
108 

64 
121 

45 
148 
152 
110 

88 
106 
101 
124 
111 

62 
102 
150 

65 
9.69 






Per cent. 
63 


1873 1874 
















182 


1874-1875... 














63 


1875-1876... 


134 

54 

173 

56 

128 

69 

66 

50 

207 

61 

135 

68 

102 

119 

135 

96 

75 

118 

38 

120 

51 

100 

56 

61 

89 

93 

75 

114 

53 

151 

164 

115 

87 

117 

121 

100 

95 

67 

123- 

163 

40 
15.51 












112 


1876-1877 


50 
144 

44 

118 

78 

71 

77 

236 

73 

152 

63 

117 

136 

156 

114 

' 78 

123 

57 

138 

54 

125 

64 

50 

78 

96 

72 

136 










47 


1877-1878 








99 

52 
88 
78 
62 


143 


1878-1879 ( 






55 


1879-1880 106 

1880-1881 89 

1881-1882 ' 101 

1882-1883 143 


""iao" 

183 
153 

97 
108 

55 
140 

62 
103 

* 78 

* 64 

70 

105 

88 

90 

.57 

142 

138 

110 

74 

112 

82 

79 

78 

76 

85 

137 

27 

40.78 


no 

76 
95 
60 

210 
76 

120 
68 

112 

59' 

134 
77 
126 
65 
57 
80 
94 
70 
118 
59 
141 
155 
119 
91 
128 

25 
14.01 


117 
81 
82 
74 


1883-1884 1 212 






232 


1884-1885 






74 


1885-1886 






147 


1886-1887 






71 


1887^-1888 ' 






110 


1888-1889 


129 

157 

116 

91 

105 

59 

149 

67 

111 

65 

53 

60 

85 

65 

96 

47 

142 

153 

120 

97 

111 

95 

104 

105 

66 

109 

145 

27 
10.88 


*"*i47' 
132 
160 
87 
125 

""86" 

86 

98 

43 

155 

133 

125 

76 

113 

86 

100 

94 

63 

99 

115 

25 
20.33 


127 


1889-1890... 


155 


1890-1891 . . . 


142 


1891-1892 

1892-1893 


77 

87 

142 

109 

41 

77 

47 

37 

70 

85 

84 

106 

53 

140 

152 

112 

85 

96 

82 

98 

92 

72 

122 

180 

29 
29 02 


95 
103 


1893-1894 




1 894-1895... 


129 


1895-1896 


60 


1896-1897 


111 


1897-1898 


60 


1898-1899... 


54 


1899-1900 


73 


1900-1901 


94 


1901-1902 . 


76 


1902-1903 


110 


1903-1904 


51 


1904-1905 . 






145 


1905-1906 






150 


1906-1907 






116 


1907-1908 






85 


1908-1909... 






112 


1909-1910 






94 


1910-1911 . 






101 


1911-1912... 


62 




91 


1912-1913 


68 


1913-1914 


105 

141 

30 
19 74 


27 
17 27 


106 


1914-1915 


147 


Number of years 




Average annual 
precipitation, in 
inches, as ob- 















a Number of stations in Tables 17 and 64. 



PRECIPITATION. 8 5 

The method of estimating the average annual precipitation at 
stations for which only short-period records are available is essentially 
that used by Hann and has been adopted as more or less standard 
by European and American meteorologists. 1 The procedure may 
be indicated algebraically as follows: 

Let m = period of years represented by short-time record at pre- 
cipitation station A. 
a = average annual precipitation at A as observed for period 
. • m. • 

N= computed average annual precipitation at A for long 
period of years (normal). 
• Sn = average annual precipitation as observed at one of the 
nine San Diego County control stations near A (normal) . 
Sm — average annual precipitation as observed at same control 
station for period m. 
K= ratio 8m/ Sn, or correction factor. 
Then, according to the method used by Hann, Sm/Sn = a/N or 
K= a/N, from which it follows that JV= a/K. 

The value of K for any group of years can be obtained from the last 
column of Table 18 by merely averaging the precipitation indices for 
the years. The computation of the estimated normal precipitation 
at any short-period station is thus simplified to a substitution in the 
equation N= a/K of values for a and K. These values have been 
computed for all precipitation stations listed in Table 17 and are 
tabulated in the next to the last column of that table. The computed 
normal precipitation for all stations of less than 25 years' record is 
entered in the last column of Table 17. These quantities are com- 
parable with each other and with the averages at the nine control 
stations, and they form the basis for the study of the geographical 
distribution of average annual precipitation. 

DISTRIBUTION OP PRECIPITATION BY TIME. 

The distribution of precipitation by days (storms), by months, and 
by years affects materially the ground-water supply in San Diego 
County. Records of daily precipitation are essential to a detailed 
study of fluctuations of the water table due to direct rainfall and 
flood run-off. Records of monthly precipitation are useful in study- 
ing precipitation as a direct source of ground water and its effect on 
monthly fluctuations of the water table. Records of annual precipi- 
tation are necessary in studying variations in annual run-off and the 
more general fluctuations of the water table. 

The distribution of precipitation by storms in San Diego County is 
well shown by the graphic record of daily precipitation at six typical 

i On working up precipitation observations; translated from Dr. Hugh Meyer's " Guide to the working 
up of meteorological observations for the benefit of climatology": U. S. Weather Bureau Monthly Weather 
Review, April, 1917. 



86 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

stations for the season 1914-15 (PI. XVI). The rainfall for each day 
is shown by an inclined line crossing the space represented by a day 
and reaching a vertical height representing the precipitation for the 
day, according to the scale at the left of the diagram. For a storm 
that lasts several days, continuous lines are drawn, one above the 
other, the end of the line representing the aggregate precipitation for 
the storm. It should be noted that few single storms last more than- 
four days, and that during the rainy season they occur at intervals 



immsiiM MustMgiHi MwmH* 






— SAN DIEGO — 
Annual 9 69 in.. 




CUYAMACA 

Annual 40.78 in. 



S 



n 



-JULIAN- 



.Annual 29.02 in. 



zti 



— ESCONDIDO— 
Annual 15.51 in. 



rf 



■POWAY- 



. Annual 14.01 in. 




■SWEETWATER DAM- 
_ Annual 10.99 in.. 





-FALLBROOK- 



Annual 17.27 in.. 



A 



iz 



•VALLEY CENTER- 



No monthly record 



Percentage of mean annual precipitation falling each month represented by heavy lines. 
Rainfall year July 1 to June 30 



Figure 5.— Monthly distribution of precipitation in San Diego County. 



of 1 to 20 days. The frequency was greater than usual in 1914-15, 
which was a very wet year (Table 18). The dry season is without 
rainfall. 

The monthly distribution is well shown by figure 5, on which the 
percentage of the average annual precipitation occurring each month 
at each of the nine control stations is represented. From these dia- 
grams it appears that 70 per cent of the precipitation occurs from 
December to March, inclusive, and practically none from June to 
September. At mountain stations, however, such as Campo and 



XJ. S. GEOLOGICAL SURVEY 


WATER-SUPPLY PAPER 446 PLATE XVI 







Season's 
total 


July 


August 




May 


June 

































00 in. 







OOin. 









28 in. 




0. OOin. 




/4.93in. 






































































Cl^ 














































a 


00 in. 




0. 


OOin. 






1. 


42/n. 




0. 


OOin. 




21. 71 in. 










































TL 


! 


























U 
















































a 


00 in. 




0. 


OOin. 






2. 


35in. 




0. 


OOin. 




25.37in. 
















1 


























L. 




























u 


1 














































a 


OOin. 




a 


OOin. 






0. 


51m 






race 




21.94 in. 










































j j 


- 
























\ 

— \ 


tL 


/-,. 


. 









































0. 


OOin. 




0. 


OOin. 


' 




2. 


56 in. 




0. 


OOin. 




23.23 in. 
















( 




























\ 


























:jll 


' 












































0. 


OOin. 




0. 


OOin. 






s 


90 in. 






Trace 




27.16 in. 
















n 


























f. 




























u 


/ 














July 


August [ 




May 


June 


Seasons 
total 





























DIAGRAMS GO COUNTY IN 1914-15. 



WATER-SUPPLY PAPER 440 PLATE XVI 











































































total 


July 


August 


September 


October | November 


December 


January 


February 


March 


April 


May 


June 












































































00 in. 




0.00 in. 




a OOin. 




' 


05in. 




86 in. 




* 


2lin. 




4.31 in. 




3.61m. 




a 


33 in. 




1 


ISin. 




a 2a in. 






OOin. 




14.33m. 










































1 








































































! 


f 


f 
















































L. 




, 


f\ 






< r J 






1 


1 




, 












r/\ 















SAN DIEGO 
















































































OOin. 






OOin. 






lOin. 




/. OS in. 




1 


35 in. 




1.85 in. 




& 


fSin. 




4. 12 in. 




l.33in. 




2 86 in 




/ 


42in. 






OOin. 




21.71 in. 
























































































































f 














l 


/ 
































I 




■ 1 


• / 






r 


ll 




r 






\ 


Jl 




1 




r 






1 I 



























































































a 


OOin. 







OOin. 






OOin 




a 


SI in. 




1 


41, n. 




2 


S5in. 




7 


06 in. 




S. 41 in. 






SSin. 




3 


72in. 




l. 35 in. 




0. 00 jn. 




25.37/n. 














































f 
















1 






















































1 


















( 


































I 






l 






' 


If 








!/ 


\ 1 


r I 


f 


1 




( 




r 


I 


1 















ESCONDIDO 













































































a 


OOin. 




0. 


OOin. 







OOin. 




1. 


41, n. 




1 


23, n. 




3. 


42 in. 




6 


51 in. 




5 75 in. 




0.50 in. 




2 


73, n. 




051 in 






'race 




21 34 in. 








































































































































































1 




1 


f 




1 


'.) 


I 1 








f 


1 J 


/ f 


, 1 






^- 






'I 


f 















OCEANSIDE 
















































































OOin. 







OOin. 




0. 


22 in. 




a 


88 in. 







76 m. 




3 


SSin. 




6 


36 in. 






47 in. 






74 in. 




1. SO in. 




* 


SB in. 




a 


OOin. 




23. 23 in. 














































1 






























































1 
















| 












































1 






I 








ll 








1 


l 






1 










/ / 


/ 


, 













4 












































































a 


OOin. 




a 


OOin. 




0. 


lOin 







46 in. 




/ 


22in. 




4. 


03 in 




7 


24 m 






39, n. 




2 


45 m 










Jl 


30 m 






Trace 




27.l6in. 


2 






























































r 
































j 












, / 








1 








r 










f 





































j 




/ 








ll 








j 


1 




1 










> 


























Hugo 






ptemt 




' Octobe 










D 






' '' 


anuary 


February 


March 


April 


May 


June 












l 


MAC, 


JAMS 


SHO 


VIN< 


.DU1 


*ATI 


)N, I 


WEN 


sm 


ANT 


>TOT 


ALP 


WAR 
REC 


NER 
PITA 


SPF 

TION 


ING 
OFS 


TOR 


USA! 


TYI 


ICA 


LST 


LTIOI 


*S IN SAN DIEGO COUNTY IN 1914-15. 









J 






Si 

i 

I 

! 



U. S. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 446 PLATE 





1 1 1 


5 5 


? S ? N S 

5 5 5 5 5 


* ? £ ? $ ? $ ? 55 5 

SH.IIMIII 


! S § S § % % % 5 5 

$_$ S !> S> S S 9 9 5 




+ 100 








































- +/SO 


+ 50 


1 




A 


VAL 
verage 


:«- 






? /$, 74/nc6es 






POH/Ay 
Average prec/pitat/on /* 0/ inches 




CAMPO 
1 verage precip/tat/bn SO. 33 nc/ias 


-+/oo 







k 


A 


JL 






ij 








Jj^SJ 


i 


j* 


i 








1 


L 


■+S0 




H 


IP 


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DIAGRAMS SHOWING VARIATION IN ANNUAL PRECIPITATION AT NINE CONTROL STATIONS IN SAN DIEGO COUNTY. 



iH 






PRECIPITATION. 87 

Cuyamaca, local thunderstorms occur during the summer. Rainfall 
during October, November, April, and May has little direct effect 
on run-off or ground water. 

Variations in annual precipitation are shown diagrammatically 
by Plate XVII for the nine control stations in San Diego County for 
the full period of record at each. The departure from the average 
is expressed as a percentage and is plotted up or down from a zero 
line representing the average. The most striking feature of the 
diagram is the wide variation from year to year and the tendency 
for wet and particularly for dry years to occur in groups or 
cycles. The maximum range of variation is from about twice to 
one-half the average. The longest consecutive cycle of dry years 
comprises about six years, and the longest consecutive cycle of wet 
years comprises three years. Precipitation in the year beginning 
July 1, 1914, and ending June 30, 1915, during which most of the 
field observations were made in connection with this report, was 47 
per cent above the average. 

GEOGRAPHIC DISTRIBUTION OF PRECIPITATION. 

A knowledge of the geographic or horizontal distribution of precipi- 
tation is important in connection with the study of run-off from 
specific areas and of absorption of water by porous alluvium and 
residium. The ground-water supply is annually replenished by 
absorption from both direct rainfall and run-off. The amount of 
precipitation over any given area, therefore, has a direct effect on 
the ground-water supply of that area and of lower areas through 
which the run-off passes. 

The horizontal distribution of precipitation in San Diego County 
is largely controlled by the topography. The situation is typical 
of that in regions characterized by a range of mountains paralleling 
a coast toward which cyclonic storms move from the bordering ocean. 
The slope leading up to the crest of the range elevates the whole 
body of moisture-laden air during its movement inland and thus 
induces more rapid condensation of moisture as a result of the cooling 
which accompanies gaseous expansion. As soon as the air reaches the 
crest and begins movement down the opposite slope condensation 
of moisture stops as a result of compression and increasing tempera- 
ture of the air. These conditions are found on all humid continental 
borders throughout the world, although in many of them the depth 
of annual precipitation exceeds that in San Diego County. On the 
west slope of the Sierra Nevada in California 1 there is a zone of maxi- 
mum precipitation between altitudes 3,500 and 5,500 feet above 



1 Henry, A. H., Average annual precipitation in the United States for the period 1871 to 1901: U. S. 
Weather Bur. Monthly Weather Review, vol. 30, p. 208, 1902. 

Lee, C H., Water resources of a part of Owens Valley, Calif.: U. S. Geol. Survey Water-Supply Paper 
294, 1912. 



88 GROUND WATERS OF WESTERN* SAN DIEGO COUNTY, CALIF. 

sea level, the amounts decreasing above the higher level. In San 
Diego County, however, the highest peaks barely reach 6,000 feet 
above sea level, so that the maximum precipitation occurs at or 
near the crest of the first range from the west. 

The great number of precipitation stations in San Diego County 
makes it feasible to study the influence of topography on precipita- 
tion in greater detail than is ordinarily possible. The results of this 
study are embodied in the map of the Pacific slope drainage areas 
of the county (PI. XV), which shows lines of equal average annual 
precipitation with 2-inch intervals. This map shows that the aver- 
age annual precipitation increases regularly from about 10 inches 
at the coast to about 45 inches at the crest of the first range, and 
that the amount of precipitation in any locality follows very closely 
the local slopes and elevations. 

The general relations of precipitation, elevation, and slope are 
well shown by the diagrams in Plate XVIII, which were prepared 
from Plate XV along vertical sections represented by lines A-A and 
B-B. The first pair of diagrams shows the relation of average 
annual precipitation and altitude and indicates a more or less uni- 
form rate of increase from the coast to the highest elevation of the 
range of about 0.6 inch in depth per 100 feet increase in elevation. 
East of the crest precipitation decreases rapidly. The second and 
third pairs of diagrams show very clearly the close relation between 
precipitation and slope. 

The method of indicating on the plate the position of lines of 
equal annual precipitation was as follows: First a diagram was 
prepared (fig. 6) on which the corrected average annual precipita- 
tion at each station (Table 17) was plotted against the elevation of 
the station (Table 17). Examination of this diagram showed that 
for all stations west of the first mountain crest precipitation and 
elevation maintained a more or less consistent relation which could 
be approximately expressed by a straight line with a slope of 0.5( 
inch of rain per 100 feet of elevation. Variations from this lin< 
were considerable but exceeded 20 per cent at only four stations. 

The first step in plotting a line of equal precipitation for a locality 
was to select pairs of stations which were not separated by pronounced 
ridges and at which precipitation was greater and less, respectively, 
than that desired. Each pair of points was then picked out on 
figure 6 and connected by a straight line. The average of the eleva- 
tions at which these lines cross the given precipitation line was then 
plotted on the map. By covering the whole area in this manner 
numerous points were plotted for each line of equal precipitation, 
and these points were then connected, the connecting line following 
the general course of the proper surface contours between the points of 
control. For areas east of the crest of the culminating range this 



S. GEOLOGICAL SURVEY 



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APHIC LOCATION AND PRECIPITATION 










































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DIAGRAMS SHOWING INFLUENCE OF TOPOGRAPHY, LOCATION, AND ALTITUDE ON PRECIPITATION IN SAN DIEGO COUNTY. 



PRECIPITATION. 



89 



method was combined with straight interpolation. In studying 
the area west of the crest it was found that the same precipitation 
occurs at progressively higher elevations from north to south across 
the county. Thus, whereas an average annual precipitation of 20 



6,600 
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3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 AQ 
AVERAGE ANNUAL PRECIPITATION, IN INCHES 

Figure 6.— Relation of altitude to long-term average annual precipitation for all stations in San 

Diego County. 

inches occurs at an elevation of about 1,500 feet at the north county 
line, at the international boundary the line of 20-inch average annual 
precipitation rises to about 2,500 feet. Similar differences in eleva- 
tion occur in all contours of precipitation exceeding 16 inches. This 
fact explains much of the variation from the average straight line 



90 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF 



as noted in figure 6. Although the lines of equal annual precipita- 
tion as shown in Plate XV are doubtless inaccurate in many details, 
it is believed that the map is sufficiently reliable to be useful to 
engineers in connection with investigations of water-supply. 

RELATION OF RUN-OFF TO PRECIPITATION. 

Two relations of run-off to precipitation are significant in connec- 
tion with the subject of ground-water supply as discussed in this 
report — variation in regard to time and percentage of precipitation 
appearing as run-off. 

Seasonal variations in run-off and precipitation are readily com- 
pared by means of figure 7, on which the average annual variation 
of precipitation at the nine control stations has been plotted together 
with the annual variation of flow of Sweetwater River at Sweet- 
water dam, San Diego River at diverting dam, and San Luis Rey 
River near Pala. (See also Table 20, p. 95.) The variation in flow 
of San Gabriel River near Azusa, in Los Angeles County, for which 
a 19-year record is available, is also shown. These diagrams show 
that although run-off follows in general the same variations as 
precipitation, it is subject to wider seasonal fluctuations than pre- 
cipitation, the maxium run-off being from 2J to 3 times the average 
run-off and the minimum being almost zero. 

The relation between daily run-off and precipitation may be seen 
by comparing Plates XVI (p. 86) and XIX (in pocket). An impor- 
tant difference at once apparent is that, although preoipitation began 
late in September or early in October, 1914, the first flood run-off 
occurred January 29, 1915, by which date about 7 inches of the season's 
precipitation had fallen. After this date every storm in which the 
precipitation was an inch or more yielded large run-off. Even smaller 
storms, such as that of March 27-29, when about 0.3 inch of rain fell, 
affected stream flow. The failure of precipitation to produce run-off 
early in the season was due to lack of moisture in the ground — 
a lack that existed both in the alluvium of the valleys and in the thin 
but widespread unconsolidated surface materials of other parts of the 
drainage areas. When the surface materials had absorbed a certain 
quantity of moisture they became saturated more easily, and the 
precipitated water then began in part to flow off the surface. Run-off 
continued, in diminishing quantity, after the last storm in May for 
two or three months, and then the streams dried up. The source of 
this flow was ground water, which continued to percolate to the 
stream channels in diminishing quantities until most of that above 
levels of the stream channels had drained out. 

A comparison of daily run-off and precipitation in seasons prior to 
to that of 1914-15 shows that the amount of precipitation before the 
date of the first flood run-off varies widely and depends largely on 



PKECIPITATIOST. 



91 



fc 55 5 eg 5> $ 



+100 



AVERAGE | 



+150 



1 

AVERAGE £Q 



AVERAGE 







-100 



$ § | 
Figure 7.— Variation in annual discharge of streams in San Diego County. 



92 GKOUND WATEKS OF WESTEKN SAN DIEGO COUNTY, CALIF. 

the degree of the precipitation in the preceding year or years and on 
the intensity of the early rains. 

In order to analyze the conditions Table 19 was prepared for four 
typical gaging stations — San Luis Rey River near Pala, Santa Ysabel 
River near Ramona, San Diego River at diverting dam, and Sweet- 
water River at Sweetwater dam. This table covers the period of 
record at each station and shows the precipitation index for each year, 
beginning July 1 (Table 18), the date of first flood run-off, the ap- 
proximate average depth of precipitation on the drainage area for each 
year, the per cent of precipitation prior to the date of first flood run-off, 
and the average depth of precipitation on the drainage area prior to the 
date of first flood run-off separated with respect to the character of the 
precipitation in the previous year, into three groups, determined for 
(1) dry years, or years following those with precipitation index less 
than 90 per cent or the second year following a year with an index of 70 
per cent or less; (2) average years, or years following those with a 
precipitation index of 90 to 110 per cent; (3) wet years, or years 
following those with a precipitation index exceeding 110 per cent, 
except the second year after one with an index of 70 per cent or 
less. The purpose of the segregation into groups was to show the 
hold-over effect, if any, of a dry or wet year on the quantity of 
moisture stored in the earth. Inspection of the last three columns 
of Table 19 shows a similarity in the depths of preoipitation required 
to produce run-off under these three conditions and thus an evident 
hold-over effect. The effect of a year in which precipitation is less 
than 70 per cent of the average appears to be noticeable for two 
years. 






PRECIPITATION. 



93 



Table 19. — Precipitation required to produce flood run-off in typical streams of San 

Diego County. 

San Luis Rey River near Pala.a 

[Drainage area, 322 square miles.] 





Precipita- 
tion index 
(percentage 
of average 
for nine 
control sta- 
tions; table 
18). 


Date of first 

flood run-off 

at gaging 

^station. 


Average 
precipita- 
tion on 
drainage 
area. 


Per cent of 
annual pre- 
cipitation 
prior to date 
of first flood 
run-off, as 
obtained 
from pre- 
cipitation 
stations on 
drainage 
area. 


Average depth of precipitation re- 
quired to produce run-off fol- 
lowing— 


Year (July 1 to 
June 30). 


A year with 

index of 89 

per cent or 

less, or the 

second year 

following 

one with 

index of 70 

per cent or 

less. 


A year 
with in- 
dex of 90 
per cent 
to 110 per 

cent. 


A year with 
index of 111 
per cent or 

more ex- 
cept second 
year after 

one with 
index years 

of 70 per 
cent or less. 


1902-03 


110 
51 
145 
150 
116 
85 
112 
94 
101 
91 
68 
106 
147 




Inches. 


Per cent. 


Inches. 


Inches. 


Inches. 


1903-04 


Mar. 23,1904 
Jan. 9, 1905 
Jan. 19,1905 
Nov. 23, 1906 
Oct. 16,1907 
Dec. 3, 1908 
Nov. 11,1909 
Jan. 10,1911 
Dec. 29,1911 
Jan. 15,1913 
Jan. 16,1913 
Jan. 22,1915 


12.8 
36.4 
37.7 
29.2 
21.3 
28.1 
23.6 
25.4 
22.8 
17.1 
26.6 
36.9 


48.7 
12.1 
21.4 

6.8 

5.3 
23.6 

4.5 
16.2 

8.7 
28.2 
23.0 
23.1 




6.2 1 




1904-05 


. 4.4 
8.1 




1905-06 






1906-07 




2.0 


1907-08 






1.1 


1908-09 


6.6 






1909-10 




1.1 


1910-11 




4.1 

.2.0 

4.8 




1911-12 






1912-13 






1913-14 


6.1 

8.5 




1914-15 


















(») 




6.7 


4.3 


1.4 













Santa Ysabel River near Ramona.c 



1904-05 


145 
150 
116 

85 
112 

94 
101 

91 

68 
106 
147 














1905-06 


Jan. 19,1906 
Dec. 7, 1906 
Dec. 7, 1907 
Jan. 9, 1909 
Nov. 11,1909 
Jan. 9, 1911 
Mar. 2, 1912 
Jan. 16,1913 
Jan. 19,1914 
Jan. 22,1915 


39.2 
30.3 
22.2 
29.2 
24.5 
26.4 
23.8 
18.3 
28.5 
39.5 


22.4 
13.1 
20.1 
19.2 
11.0 
17.8 
19.7 
28.9 
25.1 
21.8 


8.8 






1906-07 




4.0 


1907-08 






4 5 


1908-09 


5.6 






1909-10 




2.7 


1910-11 




4.7 
4.7 
5.3 




1911-12 






1912-13 






1913-14 


7.2 
8.6 




1914-15 


1 






Average . . 




(d) 




7.6 


4.9 


3.7 




1 







a Date of first flood run-off at gaging station determined from records of U. S. Geological Survey and 
Volcan Land & Water Co. ; flood flow considered as flow in excess of 14 second-feet. 

b Average for these areas, derived from PI. XV, is 24.3 inches. 

c Date of first flood run-off at gaging station determined from records of U. S. Geological Survey. Flood 
flow considered as flow in excess of 12 second-feet. 

d Average depth of seasonal precipitation from PI. XV is 26.1 inches for area of 128 square miles, and 
26.9 inches for area of 110 square miles. 

Note. — Station on Santa Ysabel Creek near Escondido, with drainage area of 128 square miles from Dec. 
17, 1905, to June 30, 1912. Station moved to Pamo, with drainage area of 110 square miles on July 1, 1912. 









94 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



Table 19. 



-Precipitation required to produce flood run-off in typical streams of San 
Diego County — Continued. 



San Diego River at diverting dam.« 
[Drainage area, 90 square miles.] 





Precipita- 
tion index 
(percentage 
of average 
for nine 
control sta- 
tions; table 
18.) 


Date of first 

flood run-off 

at gaging 

station. 


Average 
precipita- 
tion on 
drainage 
area. 


Per cent of 
annual pre- 
cipitation 
prior to date 
of first flood 
run-off, as 
obtained 
from pre- 
cipitation 
stations on 
drainage 
area. 


Average depth of precipitation re- 
quired to produce run-off fol- 
lowing — 


Year (July 1 to 
June 30). 


A year with 
index of 89 
per cent or 
less, or the 
second year 
following 
'one with 
index of 70 
per cent or 
less. 


V A year 
with in- 
dex of 90 
per cent 
to 110 per 
cent. 


A year with 
index of 111 
per cent or 

more ex- 
cept second 

year after 

one with 
index years 

of 70 per 
cent or less. 


1897-98 


60 
54 
73 
94 
76 
110* 
51 
145 
150 
116 
85 
112 
94 
101 
91 
68 
106 
147 




Inches. 


Per cent. 


Inches. 


Inches. 


Inches. 


1898-99 


Feb. 1, 1899 
Jan. 2, 1900 
Jan. 5, 1901 
Jan. 24,1902 
Jan. 26,1903 
Mar. 17,1904 
Feb. 1, 1905 
Nov. 25,1905 
Dec. 1,1906 
Oct. 13,1907 
Jan. 9, 1909 
Nov. 13,1909 
Jan. 8, 1911 
Feb. 28,1912 
Jan. 8, 1913 
Dec. 22,1914' 
Jan. 29,1915 


15.4 
20.8 
26.8 
21.7 
31.4 
14.5 
41.3 
42.8 
33.1 
24.2 
32.0 
26.8 
28.8 
25.9 
19.4 
30.2 
41.8 


45.0 
38.0 
29.1 
26.4 
37.0 
44.0 
22.1 
17.0 
15.0 
5.0 
22.0 
12.0 
19.5 
16.0 
24.7 
21.3 
29.9 


6.8 
7.9 

7.8 






1899-1900 






1900-1901 






1901-2 


5.7 




1902-3 


11.6 




1903-4 


6.4 




1904-5 


9.2 
7.3 




1905-6 






1906-7 




5.0 


1907-8 






1.2 


1908-9 


7.1 






1909-10 




3.2 


1910-11 




5.6 
4.2 
4.8 




1911-12 






1912-13 






1913-14 


6.4 
12.5 




1914-15 












Average . . . 






CO 




8.5 


5.3 


3.1 













Sweetwater River at Sweetwater dam.c 

[Drainage area, 181 square miles.] 



1886-87 


71 
110 
127 
155 
142 
95 
103 
71 
129 
60 
111 
60 
54 
73 
94 
76 
110 
51 
145 
150 
116 
85 
112 
94 
101 
91 
68 
106 
147 














1887-88 




21.9 
25.3 
30.9 
28.3 
18.9 
20.5 
14.1 
25.7 
12.0 
22.1 
12.0 
10.8 
14.6 
18.8 
15.2 
21.9 
10.2 
28.9 
29.9 
23.1 
17.0 
22.3 
18.8 
20.1 
18.2 
13.5 
21.1 
29.3 










1888-89 


Dec. 23,1888 
Dec. 23,1889 
Dec. 4, 1890 
Jan. 25,1892 
Mar. 4, 1893 
Feb. 6, 1894 
Jan. 14,1895 
Jan. 26,1896 
Feb. 18,1897 

No run-off 

Jan. 10,1899 
No run-off.... 
Feb. 5, 1901 
No run-off.... 
Mar. 25,1903 

No run-off 

Feb. 3, 1905 
Feb. 10,1906 
Dec. 27,1906 
Jan. 22,1908 
Jan. 22,1909 
Dec. 5, 1909 
Feb. 1, 1911 
Mar. 3, 1912 
Jan. 20,1913 
Jan. 26,1914 
Jan. 29,1915 


23.2 
21.7 
15.2 
32.2 

48.3 
60.5 
46.8 
52.5 
66.4 

100.0 
27.5 

100.0 
52.0 

100.0 
75.0 

100.0 
38.8 
37.2 
28.2 
29.8 
40.4 
27.3 
45.9 
25.1 
38.2 
42.3 
31.3 




5.8 




1889-90 




6.7 


1890-91 






4.3 


1891-92 . . . 






6.1 


1892-93 




9.9 

8.6 




1893-94 . 






1894-95 . . . 


12.1 




1895-96... 




6.3 


1896-97 


14.7 
12.0 

3.0 
14.6 

9.8 
15.2 
16.4 






1897-98... 






1898-99 






1899-1903 






1900-1901 . . 






1901-2 






1902-3 






1903-4 . . . 


10.2 




1904-5 


11.2 
11.1 




1905-6 






1906-7 




6.5 


1907-8 






5.1 


1908-9 


9.0 






1909-10. 




5.1 


1910-11.. 




9.2 

4.6 
.5.2 




1911-12 






1912-13 






1913-14 


9.0 
9.2 




1914-15... 


9.2 








Average . . . 






(<*) 




11.3 


7.8 


5.7 













a Date of first flood run-off at gaging station determined from records of Cuyamaca Water Co. Flood 
flow considered as flow in excess of 12 second-feet. 

b Average depth of seasonal precipitation from PI. XV is 28.5 inches. 

c Dates of first flood run-off at gaging station obtained from charts showing water stage at Sweetwater 
reservoir, furnished by Sweetwater Water Co., J. F. Covert, engineer. 

d Average depth of seasonal precipitation from PI. XV is 19.9 inches. 



PRECIPITATION. 



95 



Table 20. — Run-off from and precipitation on drainage basins of streams in San Diego 

County. 

San Luis Rey River near Pala. 

[Drainage area, 322 square miles.] 



Year (July! to June 30). 



1903-4 

1904-5 

1905-6 

1903-7 

1907-8 

1938-9... 

1909-10 

1910-11 

1911-12 

1912-13 

1913-14 

1914-15 

12-year average 



Run-off. 



Total in 
acre- 
feet.a 



7,526 
45, 303 

108,224 
86, 753 
28,323 
52, 192 
50, 132 
36,279 
19, 003 
9,350 
35, 874 

100, Oil 



48,248 



Acre- 
feet per 
square 

mile. 



23.4 
140.7 
336.0 
269.4 

88.0 
162.1 
155.7 
112.7 

59.0 

29.0 
111.4 
310.6 



149.9 



Depth on 
drainage 

area 
(inches). 



0.44 
2.63 
6.30 
5.05 
1.65 
3.04 
2.92 
2.11 
1.11 
0.54 
2.09 
5.80 



2.81 



Per cent 
of 12-year 
average. 



16 
94 

224 

180 

59 

108 

104 

75 

39 

19 

74 

207 



Average 
precipi- 
tation on 
drainage 

area 
(inches). 



12.4 
35.2 
36.5 
28.2 
20.6 
27.2 
22.8 
24.6 
22.1 
16.5 
25.8 
35.7 



25.6 



Santa Ysabel Creek near Ramona. 



1905-6 


b c 60, 471 
6 35,756 
6 12,389 
6 45,765 
6 35,191 
6 c 2, 927 
6 15,352 
d 5, 965 
d 19, 814 
d 48, 069 








39.2 
30.3 

22.2 
29.2 
24.5 
26.4 
23.8 
18.3 
28.5 
39.5 




1906-7 


279.0 

96.8 

357.0 

274.5 


5.23 
1.82 
6.70 
5.16 


131 

45 
168 
129 


17.3 


1907-8 


8.2 


1908-9 


22.9 


1909-10 


21.0 


1910-11.. 




1911-12 - 


119.9 
54.2 
180.0 
437.0 


2.25 
1.02 
3.37 
8.20 


56 

22 

73 

176 


9.5 


1912-13 


5.6 


1913-14 


11.8 


1914-15 


20.7 








27,288 


224.8 


4.22 


100 


c28.2 


14.6 







San Diego River at diverting dam. 

[Drainage area, 90 square miles./] 



1898-99 

1899-1900.. 

1900-1901 

1901-2 

1902-3 

1903-4 

1904-5 

1905-6 

1906-7 

1907-8 

1908-9 

1909-10 

1910-11 

1911-12 

1912-13 

1913-14 

1914-15 

17-year average 



909 


10 


0.19 


' 7 


15.4 


609 


7 


.13 


5 


20.8 


4,023 


45 


.84 


32 


26.8 


4,122 


46 


.86 


33 


21.7 


8,375 


93 


1.74 


67 


31.4 


638 


7 


.13 


5 


14.5 


22,036 


248 


4.65 


176 


41.3 


30, 837 


343 


6.43 


246 


42.8 


32,816 


365 


6.85 


262 


33.1 


12,091 


134. 


2.51 


96 


24.2 


19,455 


216 


4.05 


155 


32.0 


13,461 


149 


2.79 


107 


26.8 


8,345 


93 


1.74 


66 


28.8 


9,620 


107 


2.01 


77 


25.9 


5,378 


59 


1.11 


43 


19.4 


10,201 


114 


2.14 


82 


30.2 


30,593 


340 


6.38 


244 


41.8 


012,563 


139 


2.62 


100 


Ji 27. 8 



a For authority see Table 23. 

6 Data compiled f rem U. S. Geoh Survey Water Supply Paper 300. 
c Part of season only. 

d Data furnished by district engineer, U. S. Geological Survey. 

e Average depth of seasonal precipitation from PI. XV is 26.1 inches for area of 128 square miles and 
26.9 inches for area of 110 square miles. 
/ Exclusive of drainage area of 12 square miles tributary to Cuyamaca reservoir. 
ff Authority for run-off, Cuyamaca Water Co., W. S. Post, engineer. 
h Average depth of seasonal precipitation from PI. I is 28.5 inches. 

Note.— Station on Santa Ysabel Creek near Escondido, drainage area cf 128 square miles, from Dec. 17, 
1905, to June 30, 1912. Station moved to Pamo, drainage area of 110 square miles, on July 1, 1912. 



96 GROUND WATERS OF WESTERN SAN" DIEGO COUNTY, CALIF. 



Table 20. — Run-off from and precipitation on drainage basins of streams in San Diego 

County — Continued. 



Sweetwater River at Sweetwater dam. 
[Drainage area, 181 square miles.] 





Run-off. 


Average 
precipi- 
tation on 
drainage 

area 
(inches). 


Run-off 


Year (July 1 to June 30). 


Total in 
acre- 
feet. 


Acre- 
feet per 
square 

mile. 


Depth on 
drainage 

area 
(inches). 


Per cent 
of 12-year 
average. 


in per 
cent of 
precipi- 
tation. 


1887-88 

1888-83 


7,048 

25,253 

20,532 

21,565 

6,198 

16,261 

1,338 

73, 412 

1,321 

6,891 

4 

245 



828 







13, 760 

35, 000 

30,000 

4,140 

16,007 

9,619 

3,160 

5,017 

915 

3, 525 

27, 026 


38.9 

139.5 

113.2 

119.0 

31.2 

90.0 

7.4 

405.0 

7.3 

38.1 

.0 

1.4 

.0 

4.6 

.0 

.0 

.0 

76.2 

193.3 

165.8 

22.8 

88.5 

53.2 

17.5 

27.7 

5.0 

19.5 

149.5 


0.73 

2.61 

2.12 

2.23 

.64 

1.69 

.14 

7.60 

.14 

.72 

.00 

.03 

.00 

.09 

.00 

.00 

.00 

1.43 

3.63 

3.11 

.43 

1.66 

1.00 

.33 

.52 

.09 

.37 

2.80 


60.0 

214.9 

174. 7 

183.6 

52.7 

138.4 

11.4 

624. 7 

11.2 

58.6 

.0 

2.1 

.0 

7.0 

.0 

.0 

.0 

117.0 

237.8 

255.3 

35.2 

136.2 

81.8 

26.9 

42.7 

7.8 

30.0 

30.0 


21.9 

25.3 

30.9 

28.3 

18.9 

20.5 

14.1 

25.7 

12.0 

22.1 ' 

12.0 

10.8 

14.6 

18.8 

15.2 

21.9 

10.2 

28.9 

29.9 

23.1 

17.0 

22.3 

18.8 

20.1 

18.2 

13.5 

21.1 

29.3 


3.3 
10.3 


1889-90 


6.9 


1890-91 


7.9 


1891-92 


3.4 


1892-93 


8.2 


1893-91 


1.0 


1894-95 . 


29.6 


1895-96 


1.2 


1896-97 


3.3 


1897-98 


.0 


1898-99 


.3 


1899-1900 


.0 


1900-1901 


.5 


1901-2 


.0 


1902-3 


.0 


1903-4 


.0 


1904 5 


5.0 


1905-6 


12.1 


1906-7 


13.5 


1907-8 


2.5 


1908-9 


7.4 


1909-10 


5.3 


1910-11 


1.6 


1911-12 


2.9 


1912-13 


.7 


1913-14 


1.7 


1914-15 


9.6 








o 11,752 


64.9 


1.22 


100.0 


b20.2 


4.9 







San Gabriel River near Azusa. 

[Drainage area, 222 square miles.] 







Run-off. 




Season. 


Total acre- 
feet, c 


Acre-feet 

per 

square 

mile. 


Depth on 
drainage 

area 
(inches) . 


Per cent 

of 
average. 


1895-96 


d 28,661 

88,122 

26, 628 

10,490 

12,002 

92,976 

26, 518 

101,623 

32,295 

153,048 

228, 470 

349,800 

88,280 

176, 460 

144,040 

266, 780 

82, 400 

53, 141 

287, 172 

129,462 


140.4 
396.9 
120.0 
47.2 
54.1 
418.8 
119.4 
457.7 
145.4 
689.4 

1,029.1 

1,575.7 
397.7 
794.9 
648.8 

1,201.7 
371.1 
239.4 

1,293.5 
583.1 


2.63 

7.45 

2.25 

.89 

1.01 

7.85 

2.24 

8.59 

2.73 

12.92 

19.32 

29.55 

7.45 

14.90 

12.17 

22.53 

6.95 

4.49 

24.25 

10.92 




1896-97 


74 


1897-98 


22 


1898-99 


9 


1899-1900 

1900-1901 


10 

78 


1901-2 


22 


1902-3 


85 


1903-4 


27 


1904-5 


128 


1905-6 


'02 


1906-7 




1907-8 




1908-9 


m 


1909-10 


121 


1910-1 1 


224 


1911-12 


69 


1912-13 


45 


1913-14 


241 


1914-15 


109 








cll9,044 


536.2 


10.05 


100 







a Authority for run-off, Sweetwater Water Co., John F. Covert, engineer. 
b Average depth of seasonal precipitation from PI. I is 19.9 inches. 

c Authorities: U. S. Geol. Survey Water-Supply Paper 300, August 8, 1895, to June 30, 1912; district 
engineer, U. S. Geol. Survey, July 1, 1912, to June 30, 1915. 
d Part of year only. 



PKECIPITATION. 



97 



The last three columns of Table 19 are summarized in the following- 
table : 

Table 21. — Average depth of precipitation, in inches, required to produce run-off. 





First year 




Following a 




after 




year with 




yearwithless 


Following an 


more than 110 




than 90 


average year 


per cent of 


Stream. 


per cent of 


(90 to 110 


average ram- 


average rain- 


per cent of 


fall except 




fall or second 


average rain- 


second year 




year after one 


fall). 


after one with 




with 70 p er 
centor less. 




70 per cent 






or less. 


San Luis Rev River near Pala 


6.7 


4.3 


1.4 


Santa Ysabel Creek near Ramona 


7.6 


4.9 


3.7 




8.5 


5.3 


3.1 




11.3 


7.8 


5.7 







For the three mountain drainage basins that do not include any 
major river valley (the first three in Table 21) the average depth of 
precipitation required to produce run-off is 7.5 inches after a dry 
year, 4.8 inches after an average year, and 2.7 inches after a wet 
year. For Sweetwater River, however, which traverses a long allu- 
vium-filled valley before it reaches the point of measurement, the 
depths are 11.3, 7.8, and 5.7 inches respectively. The depths for 
Sweetwater Valley are probably greater than those of other major 
river valleys at corresponding points of measurement. In applying 
these determinations it is to be remembered that they are averages 
for whole drainage areas and that they do not necessarily repre- 
sent the amount of precipitation at any single station. 

The per cent of precipitation appearing as run-off in the four drain- 
age basins for which the above study was made is given in Table 
20. Wherever possible the total run-off was obtained from records 
of stream-gaging stations of the United States Geological Survey. 
For the San Luis Rey near Pala the quantity diverted by the Escon- 
dido Mutual Water Co. (Table 22) was added to the measured flow 
to determine the total run-off (Table 23). The record of run-off of 
Sweetwater River was furnished by the Sweetwater Water Co. 

Table 22. — Monthly discharge, in acre-feet, of Escondido Mutual Water Co.'s canal at 
heading near Nellie, for years ending June 30, 1904-1915. a 



Month. 


1904-5 


1905-6 


1906-7 


1907-8 


1908-9 


1909-10 


1910-11 


1911-12 


191^-13 


1913-14 


1914-15 


J' 


















1,138 

1,621 

676 
















448 

1,192 

282 












128 

64 

1,055 

153 




278 

504 


65 







88 

588 

612 

299 

432 

714 

622 

53 







77 
414 
544 
397 
852 
798 
627 
363 


101 











502 

797 

754 

392 

395 

105 


32 

22 







166 

478 

543 

1,161 

1,151 

469 
















494 

305 

487 

458 

1,332 

12 












182 

222 

530 

1,294 

716 

16 














240 

676 

924 

1,951 

891 

1,020 

230 


o 


jUSt 


o 


September 




o 


November 

December 

January 



541 

896 




1,773 

1,194 

918 


March 


April 


May 


412 




793 




Total 

1 


3,435 


1,922 


2,182 


3,473 


4,072 3,046 


4,022 


3,088 


2,960 


5,932 


6,527 



a Compiled from records in XJ. S. Geol. Survey Water-Supply Paper 411, and furnished by H. D. McGla- 
shan, district engineer. 

115536°— 19— wsp 446 7 



98 



GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



Table 23. — Annual discharge of San Luis Rey River near Pala, including Escondido 
Mutual Water Co.'s canal, for years ending June 30, 1904-1915. 

[Drainage area, 322 square miles.] 



Year. 


Observed 
run-off at 
gaging 
station 
near Pala 
(acre-feet). 


Discharge 
of canal 

at 
heading 

(acre-feet). 


Total discharge of 
San Luis Rey 
River above gag- 
ing station near 
Pala. 


» 


Acre-feet. 


Acre-feet 

per square 

mile. 


1903-4 


a 7, 526 
b 41,868 
b 106, 302 
b 84,571 
b 24, 850 
b 48, 120 
b 47,086 
c 32, 257 
d 15, 915 
e6,390 
/ 29, 942 
/ 93, 484 


No record. 
3.435 
1,922 
2,182 
3,473 
4,072 
3,046 
4,022 
3,088 
2,960 
5, 932 
6,527 






1904-5 


45,303 
108,224 
86, 753 
28,323 
52, 192 
50, 132 
36, 279 
19,003 
9,350 
35, 874 
100,011 


140.7 

336.0 

269.4 

88.0 

162.1 

155. 7 

112.7 

59.0 

29.0 

111.4 

310.6 


1905-6 


1906-7 


1907-8 


1908-9 


1909-10 


1910-11 


1911-12 


1912-13 


1913-14. . . 


1914-15 





a Discharge for Julv, August, September, and Oct. 1-8, inclusive, estimated by C. H. Lee; Oct. 9 to 
June 30, inclusive, from U. S. Geol. Survey Water-Supply Paper 300, 1913. 

b From record in U. S. Geol. Survey Water-Supply Paper 300, 1913. 

c July 1 to Dec. 31, inclusive, estimated by O. H. Lee; Jan. 1 to June 30, from U. S. Geol. Survey Water- 
Supply Paper 300, 1913. 

d July 1, 1911, to Mar. 31, 1912, estimated by C. H. Lee; Apr. 1 to May 31, from U. S. Geol. Survey Water- 
Supply Paper 331, p. 45, 1914; June, from records of Volcan Land & Water Co. 

« July 1 to Nov. 13, inclusive, from records of Volcan Land & Water Co.; Nov. 14 to June 30, data fur- 
nished by H. D. McGlashan, district engineer, U. S. Geol. Survey. 

/ Record furnished by H. D. McGlashan, district engineer, U. S. Geol. Survey. 

Note.— Canal record compiled from data in IT. S. Geol. Survey Water-Supply Paper 411 and furnished 
by H. D. McGlashan, district engineer. 

The following table summarizes the data presented in Table 20: 

Table 24. — Summary of data showing ratio, in percentage, of run-off to precipitation 

on drainage area. 



Year. 


San Luis 
Rey 
River 
near 
Pala. 


Santa 
Ysabel 

Creek 

near 

Ramona. 


San 
Diego 
River at 
divert- 
ing dam. 


Sweet- 
water 
River at 
Sweet- 
water 
dam. 


1887-88 








3.3 


1888-89 - 








10.3 


1889-90 








6.9 


1890-91 








7.9 


1891-92 '. 








3.4 


1892-93. 








8.2 


1893-94 








1 


1894-95 








29 6 


1895-96 








1 2 


1896-97 








3 3 


1897-98 










1898-99 




- 


1.2 
.6 
3.1 
4.0 
5.5 
.9 
11.3 
15.0 
20.7 
10.4 
12.6 
10.4 
6.0 
7.8 
5.7 
7.1 
15.3 


.3 


1899-1900 






o 


1900-1901 






.5 


1901-2 






o 


1902-3 






o 


1903-4 


3.5 

7.5 
17.3 
17.9 
8.0 
11.2 
12.8 
8.6 
5.0 
3.3 
8.1 
16.2 




o 


1904-5 r 




5.0 


1905-6 




12.1 


1906-7 


17.3 

• 8.2 
22.9 
21.1 


13.5 


1907-8 


2.5 


1908-9 


7.4 


1909-10 


5.3 


1910-11 


1.6 


1911-12 


9.5 
5.6 
11.8 
20.7 


2.9 


1912-13 


.7 


1913-14 


1.7 


1914-15 1 


9.6 








10.0 


14.6 


8.1 


4.9 







EVAPORATION. 99 

The run-off shown in this table for the mountain drainage areas 
above the major river valleys ranges from 0.6 to 22.9 per cent of the 
precipitation, the average being about 11 per cent. The per cent of 
run-off is largest on Santa Ysabel Creek near Ramona, where the 
average is 14.6 per cent. 

The run-off from the combined mountain and foothill area drained 
by Sweetwater River above Sweetwater dam varies in different years 
from to 29.6 per cent of the precipitation and averages 4.9 per 
cent; it certainly does not exceed the average run-off from mountain 
and foothill areas of other major river basins in San Diego County. 

SUMMARY. 

The average annual precipitation in western San Diego County 
ranges from about 10 inches along the coast to 45 inches at the crest 
of the first range of mountains, increasing about 0.56 inch for each 
100 feet of increase in elevation. East of the first range the pre- 
cipitation rapidly decreases to an annual average of about 18 inches 
in the high mountain valleys and is only slightly more than 18 inches 
on the second mountain crest. The range in annual precipitation is 
from about twice to one-half the average, and the range in annual 
run-off is from about three times to less than one-tenth the average. 

The aggregate depth of precipitation required to produce the first 
run-off in any season varies, so far as indicated by the records, from 
1.4 to 11.3 inches, the amount depending on the character of the 
stream, on the precipitation in the preceding year or years, and on 
the intensity of the early storms. 

The data indicate that the proportion of the precipitation in 
mountain areas that is discharged as run-off ranges from 0.6 to 22.9 
per cent and averages about 9 per cent. From one area that includes 
mountains, foothills, and valleys, the average is about 5 per cent. 

EVAPORATION. 

By C. H. Lee. 
EVAPORATION FROM WATER SURFACES. 

Records of evaporation from large water surf aces have been kept at 
several places in San Diego County. The earliest published record 
was obtained in the years 1889 to 1892 by the San Diego Land & 
Town Co. from a pan floating on the surface of Sweetwater reservoir 
near National City. The method of observation is well described 
in the following extract from a letter sent to the writer by Mr. 
Charles L. Fulton, who was at the reservoir during a part of the 
period and who made some of the observations. For a number of 
years Mr, Fulton has been the resident keeper of the Sweetwater 



100 GKOUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

dam and reservoir for the Sweetwater Water Co., the successor to 
the San Diego Land & Town Co.: 

The pan consisted of a section of 36-inch pipe closed at the bottom and securely 
fastened to a float or raft in the reservoir, and so arranged as to guard against ordinary 
stormy or rough water. In the center of this pan was an iron rod, the upper end of 
which was pointed. The zero point of the pan then was the top of this pointed rod, 
and at the beginning of the week the pan was filled to the point. At the end of the 
week the pan was filled to the point again by dipping water from the lake with a 
quart measure, careful account being kept of the number of quarts needed to fill the 
pan to the required point, this later being referred to a table for conversion to inches. 
If the rainfall was less than the evaporation, rainfall would be added to the measured 
evaporation for total evaporation. If the rainfall was in excess of evaporation the 
excess was dipped out and measured to the zero point of the pan. Then this was de- 
ducted from the weekly precipitation to calculate the evaporation. 









































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Figure 8.— Comparison of evaporation with temperature and precipitation at Sweetwater dam. 

The record as originally published 1 is reproduced in Table 25 and 
shows an average annual depth of evaporation of 58.7 inches during 
the four years 1889-1892. The record indicates that annual varia- 
tions in depth of evaporation are of very minor importance. The 
variations from month to month, however, are considerable, the 
depth of evaporation changing in conformity with the annual change 
in temperature and to a slight extent with humidity during storm 
periods. (See fig. 8.) 



» U. S. Geol. Survey Water-Supply Paper 81, p. 334, 1903. 



EVAPORATION. 



101 



Table 25. — Evaporation from free water surface at Sweetwater reservoir, 1889-1892. 
[Pan floating on surface of reservoir at elevation of 200 feet.] 



Month. 



Depth 

in 
inches. 



Per 

cent 

of 

year's 
total. 



1890 



Depth 

in 
inches. 



Per 

cent 
of 

year's 
total. 



1891 



Depth 

in 
inches. 



Per 

cent 

of 

year's 

total. 



1892 



Depth 

in 
inches. 



Per 

cent 

of 

year's 

total. 



Average. 



Depth 

in 
inches. 



Per 

cent 

of 

year's 

total. 



January... 
February. 

March 

April 

May 

June 

July 

August . . . 
September 
October... 
November 
December. 



1.99 
3.34 
3.38 
4.96 
5.82 
6.81 
7.40 
8.25 
7.36 

a 3. 09 
4.80 

a .25 



3.46 
5.82 
5.90 
8.65 
10.14 
11.89 
12.89 
14.40 
12.84 
5.23 
8.35 
.43 



1.59 
2.21 
3.28 
4.14 
6.14 
7.30 
7.38 
9.02 
6.48 
4.92 
5.54 
1.85 



2.65 
3.70 
5.48 
6.92 
10.26 
12.21 
12.35 
15.06 
10.83 
8.21 
9.25 



3.61 
1.35 
3.08 
3.71 
5.60 
6.03 
6.50 
8.89 
6.15 
6.31 
4.10 
2.75 



6.22 
2.33 
5.30 
6.39 
9.64 
10.38 
11.19 
15.30 
10.59 
10. 85 
7.07 
4.74 



2.54 
1.39 
3.08 
5.82 
4.67 
6.48 
8.81 
6.54 
6.27 
6.56 
4.77 
2.61 



4.26 

2.34 

5.18 

9.77 

7.84 

10. 89 

14.80 

11.00 

10.52 

11.02 

8.00 

4.38 



4.15 

3.55 

5.46 

7.93 

9.47 

11.34 

12.81 

13.94 

11.19 

8.83 

8.17 

3.16 



57.36 



100.00 



59.84 



100. 00 



58. 



100.00 



59.54 



100. 00 58. 71 



100.00 



a Heavy rains these months. 

Observations by San Diego Land & Town Co. (See U. S. Geol. Survey Water-Supply Paper 81, 
p. 344, 1903.) 

Under the direction of Mr. W. S. Post, chief engineer of the Cuya- 
maca Water Co., records of evaporation have been kept at La Mesa 
reservoir, about 8 miles northeast of San Diego, and at Cuyamaca 
reservoir, about 35 miles northeast of San Diego. The method of 
obtaining the records was the same as that used at Sweetwater 
reservoir, except that the pans were square instead of circular. The 
records as published, 1 with the addition of data more recently ob- 
tained by the company, are shown by Tables 26 and 27. The aver- 
age annual depth of evaporation at the two stations is 66.1 and 76.0 
inches, respectively, during the three-year period 1913 to 1915. 
These records indicate somewhat greater annual fluctuation than at 
Sweetwater reservoir, but the monthly variations closely correspond. 
The evaporation is apparently greater at La Mesa reservoir than at 
Sweetwater, possibly because of lower humidity and higher tempera- 
ture at the former station, although no observations are available 
definitely to show this condition. The greater evaporation at Cuya- 
maca reservoir is obviously due to the proximity of the desert and 
its low humidity. 



Am. Soc. Civil Eng. Trans., vol. 80, p. 1909, 1916. 



102 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



Table 26. — Evaporation from free water surface at La Mesa reservoir. 
[Pan floating on surface of reservoir.] 



Month. 



1913 



Depth 

in 
inches. 



Per cent 

of year's 

total. 



1914 



Depth 

in 
inches. 



Per cent 

of year's 

total. 



1915 



Depth 

in 
inches. 



Per cent 

of year's 

total. 



Average. 



Depth 

in 
inches. 



Per cent 

of year's 
total. 



January... 
February. 

March 

April 

May 

June 

July 

August . . . 
September 
October. . . 
November 
December. 

Year 



1.59 
4.23 
4.51 
6.19 
7.54 
6.98 
9.64 
8.45 
8.21 
6.46 
3.42 
2.70 



2.3 
6.0 
6.4 
8.9 
10.8 
10.0 
13.8 
12.1 
11.7 
9.2 
4.9 
3.8 



2.37 
2.94 
6.15 
6.16 
5.48 
7.76 
9.03 
8.26 
6.54 
4.47 
4.34 
2.37 



3.6 
4.5 
9.3 
9.4 
8.3 
11.8 
13.7 
12.5 
9.9 
6.8 



1.73 
2.40 
4.99 
5.15 
6.45 
8.01 
9.34 
7.89 
6.02 
5.10 
4.11 
1.44 



2.8 
3.8 
8.0 
8.2 
10.3 
12.8 
14.9 
12.6 
9.6 
8.2 
6.6 
2.3 



1.90 
3.19 
5.22 
5.83 
6.49 
7.58 
9.34 
8.20 
6.92 
5.34 
3.96 
2.17 



2.9 
4.8 
7.9 
8.8 
9.8 
11.5 
14.1 
12.4 
10.4 
8.1 
6.0 
3.2 



69.92 



100.0 



65.87 



100.0 



62.63 



100.0 



100.0 



Note. — Pan is a 3 by 3 foot standard pan 18 inches deep, 
maca Water Co. 



Elevation, 480 feet. Observations by Cuya- 



Table 27. — Evaporation from free water surface at Cuyamaca reservoir. 
[Pan floating on surface of reservoir.] 





1913 


1914 


1915 


Average. 


Month. 


Depth 

in 
inches. 


Per cent 

of year's 

total. 


Depth 

in 
inches. 


Per cent 

of year's 

total. 


Depth 

in 
inches. 


Per cent 

of year's 

total. 


Depth 

in 
inches. 


Per cent 

of year's 

total. 


January 






a 3. 28 
a 5. 46 
7.20 
5.60 
7.53 
8.99 
9.90 
10.76 
7.53 
6.08 
3.28 
3.94 


4.12 
6.85 
9.05 
7.03 
9.47 
11.29 
12.46 
13.53 
9.46 
7.66 
4.12 
4.96 


3.47 
3.97 
4.56 
3.75 
4.52 
9.66 
8.74 
10.30 
7.16 
8.30 
3.99 
4.88 


4.73 
5.42 
6.23 
5.11 
6.16 
13.18 
11.91 
14.05 
9.78 
11.31 
5.45 
6.67 


3.38 
4.72 
5.88 
4.68 
6.02 
9.30 
8.94 
9.67 
8.12 
7.08 
4.30 
3.89 


4.45 








6.21 


March 






7.74 


April 






6.16 


May 1 




7.92 




9.25 
8.18 
7.94 
9.68 
6.86 
5.63 
2.85 




12.23 


July 

August 

September 

October 




11.77 




12.73 




10.69 




9.32 


November 




5.66 


December 




5.12 








Year 






79.55 


100.00 


73.30 


100.00 


75.98 


100.00 


1 







a Excessive rains overflowed pans; interpolated Jan. 13-20, 20-28, and Feb. 17-24. 

Note. — Pan is a 3 by 3 foot standard pan 18 inches deep. Elevation, 4,620 feet. Observations by the 
Cuyamaca Water Co. 

An interesting comparison of the depth of evaporation from a pan 
floating on the surface of a large reservoir with that from a whole res- 
ervoir surface, considered as an immense evaporating pan, can be made 
in connection with the record obtained at La Mesa reservoir. The 
Upper Otay reservoir, situated at about the same elevation and the 
same distance from the coast as La Mesa reservoir and 1 1 miles farther 
southeast, was not drawn upon nor did it receive accessions during 
the period January, 1913, to December, 1915. A record of the water 
level was kept at the reservoir and observations of rainfall were made 
at Lower Otay dam about 2J miles away. The net movement of 
the reservoir surface after correcting for rainfall is considered due 
to evaporation from the surface of the reservoir, since the formation 
surrounding the reservoir is practically water-tight. The data 






EVAPORATION. 



103 



have been compiled by H. A. Whitney x and are reproduced in 
Table 28. The depths of evaporation as measured in the pan at 
La Mesa reservoir and computed from reservoir levels as Upper 
Otay reservoir have been placed in parallel columns, together with 
the monthly and annual per cent of the former to the latter. The 
average for the three-year period is 94 per cent. Assuming that 
the factors affecting evaporation were the same at the two reser- 
voirs, that there was no underflow into or out from the Upper Otay 
reservoir, and that the rainfall on the Upper Otay reservoir was the 
same as at the point where the rain gage was maintained, it would 
appear that the rate of evaporation is slightly greater from a floating 
pan than from the whole of the large surface upon which the pan is 
floating. In a similar comparison in Owens Valley,- Calif., between 
the evaporation from the surface of Owens Lake and a pan floating 
on the surface of Owens River, 20 miles north of the lake, conditions 
of evaporation being similar, the writer found the two to agree 
within 1 per cent. This subject requires further investigation, but 
the writer believes that a comparison made between a whole reser- 
voir surface and a pan floating upon the surface of the same reser- 
voir, if carried out under favorable conditions for measurement of 
reservoir stage, draft, and accession, would show the rate of loss from 
the whole reservoir surface to. be very little less than that from the 
pan. The most important factor tending to make a difference 
is "probably the higher temperature of water in the pan during the 
day, as compared with that of the surrounding water, resulting from 
the absorption of solar heat by the pan. Observations of tempera- 
tures made by the writer have indicated that water temperatures in 
and surrounding the pan do not differ by more than 1° or 2° F. 
during the hot part of the day. 

Table 28. — Comparison of depths of evaporation, in inches, measured by floating pan at 
La Mesa reservoir with those computed from reservoir levels at Upper Otay reservoir. 





1913 


1914 


1915 


Average. 


Month. 


A. 

La 
Mesa 
reser- 
voir. 


B. 

Upper 
Otay 
reser- 
voir. 


Ratio 

»<! 

(per 
dent). 


A. 

La 
Mesa 
reser- 
voir. 


B. 

Upper 
Otay 
reser- 
voir. 


Ratio 

(per 
cent.) 


A. 
La 

Mesa 
reser- 
voir. 


B. 
Upper 
Otay 
reser- 
voir. 


Ratio 

«'| 

(per 
cent). 


A. 
La 

Mesa 
reser- 
voir. 


B. 

Upper 
Otay 
reser- 
voir. 


Ratio 

(per 

cent). 


January 

February 

March 


1.59 
4.23 
4.51 
6.19 
7.54 
6.98 
9.64 
8.45 
8.21 
6.46 
3.42 
2.70 


2.50 
3.00 
3.00 
4.30 
5.00 
5.80 
8.70 
8.00 
6.00 
5.00 
6.10 
3.70 


157 
71 
66 
70 
66 
83 
90 
95 
73 
77 
179 
137 


2.37 
2.94 
6.15 
6.16 
5.48 
7.76 
9.03 
8.26 
6.54 
4.47 
4.34 
2.37 


2.70 
3.40 
5.90 
6.70 
7.20 
6.70 
8.80 
8.00 
7.00 
5.00 
3.40 
2.70 


114 

116 

96 

109 

131 

86 

98 

97 

107 

112 

78 

114 


1.73 
2.40 
4.99 
5.15 
6.45 
8.01 
9.34 
7.89 
6.02 
5.10 
4.11 
1.44 


2.40 
2.90 
2.90 
4.10 
7.90 
6.00 
8.00 
8.00 
5.00 
4.00 
4.70 
2.30 


139 

121 

58 

80 

123 

75 

86 

101 

83 

78 

114 

160 


1.93 
3.19 
5.22 
5.83 
6.49 
7.58 
9.34 
8.20 
6.92 
5.34 
3.96 
2.17 


2.53 
3.10 
3.93 
5.03 
6.70 
6.17 
8.50 
8.00 
6.00 
4.67 
4.73 
2.90 


131 
97 

75 


April 


86 


May 


103 


June 


81 


July 


91 


August 


98 


September 

October 

November 

December 


87 
88 
119 
134 




69.92 


61.1 


87.5 


65.87 


. 67. 50 


102.5 


62.63 


58.20 


92.9 


66.17 


62.26 


94.2 



i Am. Soc. Civil Eng. Trans., vol. 80, pp. 1894-1989, 1916. 



104 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

In conclusion, it can be stated that the average annual depth 
of evaporation observed during short periods in floating pans at 
the three localities in San Diego County ranged from about 58 
inches near the coast to about 76 inches in a high valley that opens 
toward the desert at the crest of the divide. Variations in annual 
evaporation are very small. Variations in monthly evaporation 
generally follow variations in air temperature, with slight modifica- 
tions resulting from abnormal humidity during stormy weather. 

EVAPORATION FROM SOIL. 

The relation between the depth of evaporation from a large water 
surface and from damp bare soil is not direct, since the rate of 
evaporation from soil varies widely, depending on the depth of 
the zone of saturation below the land surface and the height to 
which water is drawn by capillary action. The maximum depth 
from which water is drawn by capillarity ranges for most soils 
between 4 and 9 feet, depending on the character of the soil. If 
the depth to ground water is more than 9 feet, the evaporation 
from the soil is zero, 1 according to the best experimental evidence, 
except as the surface is temporarily moistened by precipitation or 
flooding. If, on the other hand, the surface soil is permanently 
saturated, the rate of evaporation is but slightly less than, or pos- 
sibly equal to that from a free water surface. This fact has been 
shown by the experiments of Ebermayer 2 and also recent experi- 
ments by the United States Department of Agriculture and by 
the writer. If the surface is covered by close-growing plants or 
trees, the combined rates of evaporation and transpiration differ 
from that of bare soil. The determination of evaporation from 
soil moistened by ground water and of transpiration is thus impos- 
sible without detailed information of conditions of surface and soil 
and depth to ground water throughout the area. Such information 
can be obtained only by careful and extended field surveys, and is 
beyond the scope of this report. 

In this connection, however, the data presented later in this 
report (pp. 143-146) with regard to the annual replenishment of the 
closed basins represented by the major river valleys is of interest. 
As is shown, the porous alluvial fill of these valleys absorbs water 
from precipitation directly and from the streams that flow over 
the surface of the fill. It loses this water by evaporation from 
the surface layer of the fill as moistened by capillary water drawn 
up from the zone of saturation and by transpiration from vegetation. 
Considered for a period of years, the average annual absorption 
equals the average annual loss. The average annual absorption can 

i Lee, C. H., U . S. Geol. Survey Water-Supply Paper 294, 1912. 
2 Hough, F. B., Report on forestry, U. S. Dept. Agr., 1877. 






EVAPORATION. 105 

be computed for the various major valleys, as explained on pages 
143-146. In San Luis Rey Valley the average annual absorption has 
been determined as 14,450 acre-feet. The writer has made a detailed 
field examination of the surface of the valley fill of this valley below 
the gaging station of the United States Geological Survey near 
Pala and has segregated and mapped all lands from which soil 
evaporation and transpiration occur through part or all of the year. 
The total area of such lands was found to be 6,640 acres. The 
remaining 1,006 acres of valley fill was bare land beneath which 
the zone of saturation was at too great a depth for ground water 
to be drawn to the surface by capillarity. By dividing the average 
annual absorption of the valley fill by the land area from which 
this volume is annually dissipated into the atmosphere, it appears 
that the average depth of water lost each year is 2.19 feet. This 
result checks within 10 per cent that reached independently from 
a detailed study of evaporation and transpiration from soil in this 
valley by using the principles developed by work in Owens Valley 1 
and other experiments, but modifying their application to conform 
with the local conditions as to soil, evaporation from free water 
surface, and type and density of vegetation. The natural conditions 
in other major valleys of San Diego County are similar to those in 
San Luis Rey Valley, although the ground-water supply has been 
more extensively used in some of them. This determination, how- 
ever — 2.19 feet — can be considered as approximately representing 
the average annual depth of water discharged by evaporation from 
moist lands and transpiration from natural vegetation in the major 
river valleys of the county. 

METHOD OF DISCUSSING GROUND WATER BY AREAS. 

To facilitate discussion San Diego County may be divided into the 
following groups of areas with respect to the occurrence of ground 
water: (1) Major valleys, comprising the valleys of the six largest 
streams of the county; (2) minor valleys of the coastal belt; (3) minor 
valleys of the highland area; (4) Nestor and Chula Vista sea terraces, 
adjacent to San Diego Bay; (5) interstream areas underlain by 
Tertiary and older sedimentary formations; (6) highland areas under- 
lain by crystalline rocks not covered by residuum; (7) highland areas 
in the gently sloping and level parts of which the crystalline rocks 
are overlain by water-bearing rock waste. 

Although areas belonging to the first group constitute only a small 
part of the total area of the county, they are by far the most important 
as sources of water supply. The other areas possess in the aggregate 
a greater quantity of stored ground water, but are not capable of yield- 

1 Lee, C. H., The determination of safe yield of underground reservoirs of the closed-basin type: Am. 
Soc. Civil Eng. Trans., vol. 78, p. 148, 1915. 



106 GROUND WATEKS OF WESTERN SAN DIEGO COUNTY, CALIF. 

ing large quantities at any one point, and hence are not adapted to 
utilization by big single plants. At many localities in these areas, 
however, small but reliable supplies of ground water can be obtained. 
The discussion of the ground water of the major river valleys 
includes descriptions of the topography and drainage of the valleys, 
underground reservoirs, the valley fill, form and fluctuations of the 
water table, yield of ground water, and methods of constructing wells, 
and it is followed by descriptions of the ground-water supply in the 
minor valleys and in other areas. 

WATER IN THE MAJOR VALLEYS. 

By C. H. Lee. 

TOPOGRAPHY AND DRAINAGE OF THE VALLEYS. 

RELATION OF VALLEYS TO ADJACENT AREAS. 

The major valleys of San Diego County, as here described, are the 
narrow, flat-bottomed valleys that extend inland from the coast 20 
to 25 miles and are traversed by streams that rise in the culminating 
mountain ranges and discharge into the Pacific Ocean. The desert 
region east of the culminating ranges is drained in part into the Salton 
Sea and in part into the Gulf of California. 

The streams that occupy the major valleys west of the divide, 
named in order from north to south, are Santa Margarita, San Luis 
Key, San Dieguito, San Diego, Sweetwater, and Tia Juana rivers. (See 
Pis. XX to XXV.) From the valleys of these streams steep slopes 
lead up to the bordering terraces or mountains. The range in which 
these streams rise has an average elevation above sea level of about 
5,500 feet, and in a few places exceeds 6,000 feet. It is dissected 
by valleys and wide canyons into more or less isolated mountains, 
such as the Agua Tibia Mountains, the Palomar Mountains, and the 
Ysidro Mountains at the head of San Luis Rey River, the Volcan 
Mountains at the head of Santa Ysabel Creek, and the Cuyamaca 
Mountains at the head of Cottonwood Creek, which is a tributary of 
Tia Juana River in the United States. 

The major valleys trend from northeast to southwest and in general 
parallel one another, at intervals ranging from 3 to 15 miles, from the 
vicinity of the north line of the county to the international boundary 
(PL II). Most of the valleys head in the highland area and extend 
more or less continuously to the coast. For the upper 12 to 18 miles 
of their length they are bordered by the mountains and foothills of 
the highland area, and for the lower 6 to 8 miles by the terraces or 
" mesas " of the coastal belt. The unconsolidated alluvial material that 
underlies the floors of these valleys is porous and contains much 
ground water. 



117 c 



1s,K 



3NYD£R&BLACK,N.Y. 




EXPLANATION 



Fill of minor valleys 



San Diego formation 

underlying Nestor 

nd Chula Vista terraces 



Tf 



Contours of water table, Jan. 6, 1915 
Contour interval 2 feet 
Datum is mean sea level 

\\w \ 

\\ \ 

I \ \ l I 

Approximate contours 

of water table, Jan. 6,1916 

Contour interval 2 feet 

Datum is mean sea level 



Contours of water table, Mar. 1, 1915 
Contour interval 2 feet 
Datum is mean sea level 



Observation well 



Tested pumping plant 



Geologic cross section 



Section showing water table 



MAP OF PART OF SAN DIEGO BAY REGION, CALIFORNIA" 

Showing principal water- bearing formations, contours of water table, 
and tested pumping plants 



-\' 







i o mm 
1 




vaiieyss 




Fill of minor valleys 



a 



Contours of water table 
October 18, 1914 



Contours of water table 
February 18, 1915 



Observation well 



Well for which log is 
available 



Tested pumping plant 



A 



Geologic cross section 

-A £. 

Section showing water table 



SNYDER &BLACK.N.Y. 



©, 



-. i.Fi'l.in.h .u M'i:\-k\ 



WATER-SUPPLY PAEEB 446 PLATE XXI 



<fvUv 




l/ANU S 



m i 



* 1 O N 



i >: 



XL. B G O 





MAP OF MISSION VALLEY, CALIFORNIA 

Showing principal water-bearing formations, contours of the water table, 
observation wells, and tested pumping plants 

Scale Safeo 



EXPLANATIOr 



□ 



Kill .it minor valleys 



E 



Observation well 



Tested pumping plant 



Geologic cross sectio 



Section showing water table 



Contour mteii-al'Jfi ii-.-t . 



WATEK IN THE MAJOR VALLEYS. 107 

The major valleys and their streams are among the valuable assets 
of San Diego County. The valley floors, though not desirable as 
places of residence because of their low elevation and liability to be 
overflowed, are well adapted to the raising of such field crops as alfalfa 
and vegetables and also to dairying. They comprise, in fact, the 
largest single bodies of land in the county adapted to such uses, and 
the local demand for their products will increase rapidly with increase 
in the population of the adjacent slopes. The water, both surface 
and underground, which these valleys afford, is their greatest element 
of value to the county. The most thickly populated parts of the 
county and the most productive agricultural lands depend either 
directly or indirectly on this water supply. The foothills and terrace 
lands are largely supplied by gravity from surface storage reservoirs 
which are filled from the winter flow of the streams that traverse the 
valleys. In periods of severe drought, when the supply of surface 
water has proved insufficient, heavy drafts have been made on the 
ground water stored in the fill of these valleys. In recent years 
pumping plants utilizing the ground waters have been established in 
these valleys to provide water not only for the irrigation of the valley 
lands, but for domestic use and irrigation on the adjacent " mesas' ' or 
terraces. Without the water supply available from these valleys, 
therefore, the foothills and coastal " mesas" of San Diego County 
would be practically uninhabitable. 

COASTAL VALLEYS. 

As shown by Plates XX to XXV, the major valleys consist of 
several more or less distinct parts. Where they cross formations of 
resistant rock they are narrow and in some places are deep canyons ; 
where they traverse softer formations they are wide and flat-bottomed. 
Each of the principal rivers, therefore, passes alternately through 
narrow gorges and wide, steep-walled basins. A few of the canyons 
contain some valley fill; others, such as the canyon at the head of 
Mission Valley, have floors of bedrock. The wide parts of the major 
valleys, formed where they cross the coastal belt, are referred to in 
this report as coastal valleys; those that are situated in the highland 
area are referred to as highland valleys. The coastal valleys extend 
inland from 6 to 8 miles from the coast and as a rule are broader than 
the highland valleys. The narrow, sand-floored canyons or rocky 
gorges that separate the coastal from the highland valleys are 4 to 6 
miles long. 

The principal coastal valleys are Santa Margarita Valley below 
Deluz station on the abandoned Fallbrook branch of the Santa Fe 
Railway, San Luis Rey Valley below Guajome ranch, San Dieguito 
Valley, Mission Valley (on San Diego River), Sweetwater Valley 
below Sweetwater dam, and Tia Juana Valley. These valleys lie 



108 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

entirely within the area underlain by sedimentary rocks (see PI. III). 
They vary in width from a quarter of a mile to 1£ miles and are sharply 
separated from the bordering terraces or " mesas" by steep slopes and 
bluffs 200 to 400 feet high. Their floors are nearly level but slope 
downstream 9 to 12 feet per mile. Some of the valleys, such as Tia 
Juana, open directly into the ocean ; others, such as San Luis Rey, are 
contracted at the mouth, so that the stream finds its outlet to the 
ocean through a canyon. The areas of these valleys range from 4,380 
acres in Tia Juana Valley to 1,532 acres in Sweetwater Valley, the ag- 
gregate area of coastal valleys in the county being 17,500 acres. (See 
Table 40, p. 151.) These figures represent the areas underlain by the 
main body of valley fill but do not include small tributary valleys. 

HIGHLAND VALLEYS. 

The highland valleys traversed by the major streams comprise the 
valley of San Luis Rey River between the east boundary of the Pala 
Indian Reservation and Bonsall, and possibly also the river valley 
within and between the Pauma land grant and the Rincon Indian 
Reservation, San Pasqual Valley and Santa Ysabel Creek Valley to 
Bernardo, the valley of San Diego River from the east boundary of 
El Cajon land grant to the Old Mission dam (including the valley of 
San Vicente Creek below Foster), and Dehesa and Jamacho valleys on 
Sweetwater River. These valleys lie wholly within the highland area 
and are underlain by granitic rocks. Most of them are definitely 
outlined by steep rocky slopes and are surrounded by the irregular 
mountains and high valleys of the highland area. The valleys vary 
from a few hundred feet to half a mile in width. Some of the con- 
necting gorges are barely 400 feet wide. The valley floors are nearly 
level but have slopes downstream of 13 to 25 feet per mile, the 
steepest slope being at the head of the highest valley on each stream. 
At the same relative distance from the coast the slopes in different 
valleys closely correspond. The areas of these valleys range from 
4,476 acres for the valley of San Luis Rey River to 1,065 acres for 
the upper Sweetwater Valley, the aggregate area of the highland 
valleys being 10,540 acres. (See Table 40, p. 151). 

SURFACE WATERS. 

The streams obtain most of their water from the upper parts of the 
highland area. Tributaries that enter farther downstream seldom add 
greatly to the flow of the stream. The main streams range in length 
from 40 to 55 miles. Their drainage basins, including highland area 
and coastal belt, range in size (excluding Tia Juana River, for which 
data are incomplete) from 780 square miles for Santa Margarita River 
to 181 square miles for Sweetwater River. The total area tributary 
to all the principal rivers (excluding Tia Juana River) is 2,280 square 



U. S. GE0LOG1 






\u\\\llS 
II 



i\ 



■ 



1 



11 



I 
Hi 



ill i' In 






Shi 



I IKOl.tK.ll'AL SURVEY WATER-SITIM.Y I'At'Ki: I- II'. I'l.MI Will 



117-15' " ~ I 


j. . \W* ! ^. j 

\ 1 1 \ (^ 

' U si 1 .,,,-' .■'■■'*■ 


\ (&i ; : b- 1 J 

• ... 1 i 


I ■ — 


- ' J^r s ,™, 



MAP OF SAN DIEGUITO VALLEY, CALIFORNIA 
Showing valley fill and location of observation well and gaging station 



Contour iiitoi-v.ai'olW'l. 

1919. 
EXPLANATION 



3 ra 



Shallow valley fill 



"VST A TITPT3 T"\T T<TTT? ~\T A TTkTJ VATTPVC 



mo 



1X3 




G>. 



. GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER +40 PLATE XXIV 




WATER IN THE MAJOR VALLEYS. 



109 



miles (Table 29 and PI. XV). Comparison of this area with the 
total area of the major valleys shows that the latter comprise only 
2 per cent of the tributary drainage basins. 

Table 29. — Areas of drainage basins tributary to streams at gaging stations in San Diego 

County. 



Stream. 


Gaging station. 


Total area 
above 
gaging 
station. 




Near Temecula 


Square 
miles. 
420± 


Santa Margarita River 


Near Ysidora 


780 ± 




Near Mesa Grande 


209 


Do 


Near Nellie (Escondido intake) 


240 


Do 


Near Pala 


«322 


Do 


Bonsall 


465 


Do 


Oceanside (opposite Oceanside pumping 

plant). 
Near Santa Ysabel 


563 




12.8 


Do 


Near Ramona 


6110 


Do 


Near Escondido 


128 


Do 


Bernardo 


266 




Near Del Mar 


328 






57.3 


Guejito Creek 


iSiear Escondido 


27.6 


Boulder Creek 




12.0 


San Diego River 


Diverting dam 


cl02.0 


Do 




* <*203 


Do 


Near Santee (Old Mission dam) 


375 


Do.. 


Near San Diego (Murray ford) 


431 




Foster 


74.9 






«43.7 


Do 




112 


Do 


Sweetwater dam 


/181 


Otay River 


Lower Otay dam 


98.6 


Cottonwood Creek 


Barrett dam 


246 








1 





a Formerly published as 318 square miles. 
b Formerly published as 113 square miles. 

c Area above diverting dam exclusive of 12 square miles tributary to Cuyamaca reservoir is 90 square 
miles. 
d Formerly published as 208 square miles. 
e Formerly published as 40 square miles. 
/ Formerly published as 186 square miles. 

Precipitation of sufficient magnitude to produce run-off is largely 
confined to the winter months — January to April — when the county 
is visited by the general storms that are common to the whole Pacific 
coast. Run-off is rapid and stream flow is at its maximum during the 
storms. The principal streams seldom flow after the first of July, 
except San Luis Rey River near Pala. As a result of the similarity of 
surface conditions and precipitation, the run-off of the streams is 
similar. The records of daily flow of San Luis Rey, Santa Ysabel, 
San Diego, and Tia Juana rivers in this region (PI. XIX), show a 
remarkable agreement both as to dates of critical stages of flow and 
relative rates of discharge. 

SOILS AND VEGETATION. 

The soil of all the valleys is composed of sand and silt derived 
mainly from the granitic rocks of the highland area but in part from 
the Tertiary formations of the coastal belt. Silty soils cover larger 






110 

areas in the coastal valleys than in the highland valleys. This material 
has all been deposited at some time by the river that traverses the 
valley, and the fertility of the soil depends largely on the decomposi- 
tion that has taken place. 

Before they were settled and cultivated the valleys supported 
growths of willow, cottonwood, alder, and sycamore trees, and more 
or less underbrush. Salt grass, yerba mansa, and swamp vegetation 
occupied open areas where the water table (see p. 123) commonly stood 
within 5 feet of the surface. As a result of settlement and cultivation 
much of the original vegetation has been removed and replaced with 
field crops, but there still remain considerable areas of natural 
vegetation, especially in the upper San Luis Rey and Sweetwater 
valleys. The destructive effect in times of flood of removing trees 
along the river channels is becoming more and more apparent. 

The slopes of the culminating range are covered by brush of varying 
density but the valle}^s are bare except for range grasses. Groves of 
coniferous trees grow at elevations of 5,000 feet and higher. Scattered 
oak trees are common at all levels along the margins of valleys and 
in canyons and in all other localities where soil and water supply are 
favorable. 

The surface of the coastal area is only gently undulating, the 
formations that underlie it consist largely of gravel and sand inter- 
bedded with clay, and the soils do not readily absorb water. There is 
little vegetation other than the short range grass which grows during 
the rainy season. 

UNDERGROUND RESERVOIRS. 

SOURCES OF WATER. 

As compared with the valley fill, the rocks surrounding both the 
highland and coastal valleys are practically impervious to the pas- 
sage of water. The crystalline rocks of the highland area are dense 
and contain recoverable water only in the fissures that traverse them. 
The voids in the conglomerate and some of the sandstones of the 
sedimentary formations are filled with clay or other impervious 
material. Well logs and other data show that hard, impervious 
formations, undoubtedly the same as those that underlie the uplands 
adjoining the valleys lie beneath the valleys at depths nowhere 
exceeding 215 feet. These logs also show that underlying the valleys 
and filling the basins formed by the bedrock there are bodies of 
porous, unconsolidated alluvial material which is composed of silt, 
sand, and gravel and is saturated with water almost to the surface. 
The water is derived chiefly by absorption and percolation of surface 
water as it flows over the valley fill; it escapes either by seeping into 
the stream channels at the lower ends of the basins, by underflow 
through the fill into the next lower basins, by evaporation from the 






WATEK m THE MAJOR VALLEYS. Ill 

soil, or by transpiration from plant surfaces. Additions to the supply 
are accompanied by a rise of the water table; withdrawals from the 
supply lower the water table. These relatively water-tight bedrock 
basins filled with porous material constitute reservoirs of underground 
water. It is as though the present valleys and canyons were to be 
closed at their lower ends by high dams and the reservoirs thus 
formed were to be filled with sand and gravel transported by the 
tributary streams. The capacity of such reservoirs to store water 
would be reduced thereby, but the action of the reservoir, its filling 
and emptying, and the rise and fall of its water surface, would differ 
but little from that of a surface reservoir. 

The following discussion of these ground-water reservoirs includes 
descriptions of the valley fill, the form and fluctuations of the water 
table, yield of ground water, and methods of reconstructing wells. 

THE VALLEY FILL. 
COASTAL VALLEYS. 

Origin of the deposits. — Information concerning the valley fill is 
obtained from geologic formations, structural features exposed at the 
surface, and the records of materials penetrated in wells. 

The geology and physiography of San Diego County indicate that 
the present position of the land with respect to the ocean level is one 
of many that it has occupied at various times. (See pp. 21-34.) The 
land surface has been both higher and lower than at present. At the 
time of its greatest elevation deep valleys were excavated, of which 
the present valleys are only the upper portions. The bottoms of 
these ancient valleys, though having the same general shape as at 
present, were narrower and deeper than those of the present valleys, 
and they were traversed by rapidly flowing streams that were actively 
cutting and widening the canyons in which they flowed. In some 
places the streams flowed near the middle of the canyon bottoms 
without much tendency to work toward either side; in other places 
the current was so directed that it undercut one of the canyon walls. 
At such places steep slopes or cliffs were created, the upper parts of 
which can still be identified by the configuration of the valley and the 
steep slope of the bluff above the present valley floor, as, for example, 
at the north end of geologic section B-B (PL XXI) in Mission Valley 
(fig. 11, p. 114), at the south end of section A-A (PI. XXI) in the 
same valley (fig. 12), and at and directly west of the south end of 
geologic section A-A (PL XXI) in San Luis Rey Valley (fig. 14). 
As explained later (p. 115) these indications are of great assistance in 
determining the best places for wells in the valley fill. 

When these valleys had been cut to depths of 400 to 500 feet the 
sea began to advance inland, submerging the land and converting 
the river valleys into narrow estuaries or salt-water bays. The 



112 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

rivers which formerly flowed rapidly through the valleys, carrying 
their loads of gravel, sand, and silt to the old shoreline, now deposited 
great quantities of alluvial debris on the submerged valley bottoms. 
Most of the coarse sand and gravel was deposited at the heads of the 
bays, but the fine sands and silts were carried farther. Submergence 
continued followed by emergence of the land, with the result that 
to-day these inland bays are completely filled with alluvial materia 
which at the heads of some of the valleys has been built up to an 
elevation 100 feet above the present sea level. Thus have the ancient 
coastal stream valleys been converted into the modern underground 
reservoirs. 

Tia J nana Valley. — Prior to its submergence Tia Juana Valley was 
the largest of the coastal valleys, the bottom being nearly a mile 
wide for a distance of 4 miles back from the present coast line (figs. 
9 and 10). The bedrock floor of the valley was almost level trans- 




4,000 5,000 6,000 

DISTANCE. IN FEET 



8,000 



9,000 



EXPLANATION 



Sand.coarse to fine 
(waterbearing) 



Gravel 
(waterbearing) 



Sandy and 
gravelly clay 



Figure 9.— Diagrammatic cross section of Tia Juana Valley along line E-E, Plate XX. 

versely and consisted of the upper surface of a layer of dark-colored 
shale which contains many fossil shells and which, because of its 
consistency when brought to the surface in drilling operations, the 
well drillers call "black mud." This material underlies a consid- 
erable portion of the valley and adjacent areas, as shown by logs of wells 
O 133, 121, O 124, 112, O 42, and others (Pis. XXVI and XXVII). 
The valley fill consists of a continuous layer of coarse gravel and 
boulders of the size of cobbles'tones, from 10 to 35 feet thick, over- 
lain by layers of sand and silt. The sand grains range from coarse 
to fine, the percentage of coarse sand being much greater at the 
upper end of the valley than at the lower. The sand and silt are 
roughly bedded, although the beds do not appear to be continuous 
over large areas. The thickness of the sand varies from a max- 
imum of 90 feet at the lower end of the valley to less than 50 feet 
at the upper end. The total depth of the fill in the lower part of 
the valley is about 100 feet; its depth in the upper part of the valley 
is not known, but is probably somewhat less than in the lower part. 



CAlj WATER-SUPPLY PAPER 446 PLATE XXVI 

Well 124 



Well 0134 

Approxim 



E1.43.0ft. 



k 

vi 



20 



40 



60 



80 



100 



120 




Soft sat 
clay 



El. 25.0 ft. 



Sand (good water) 



Bouldefi Gravel (very 
black rrt good water) 
(shale} 73' 



83' 



140 



20 



ft 40 



Well 0125 



— 10 



:<?.-?i?.oi» 



Alternate layers 
sand and silt 



Sand and gravel 
(very good water) 



Black mud (shale) 
100 ' 



20 



Well 0132 



El. 25.0 ft. 



<0 60 

VI 



80 



8 



^ 100 



120 — 



140 



El. 30.0 ft? 



Alternat 
sand an 



Gravel 
(goodwi 



74' 



Heavy silt 



°o°o»o' 

.°o«S'°« . '. 





& 




*> 


40 


X) 




4? 




c> 




>i 


80 






$ 




^ 




(v 




h- 


80 


& 




v 




* 




> 


100 


f*1 



120 



140 



Alternate layers, 
silt and sand 



Gi~avel 
(good water) 

68' 



Clean gravel 



Blue mud (shale) 

with shells 
37' 



20 



40 



60 



80 



100 



120 



140 



! 

% 



3126 Well 0124 



'--■- 










'?-? 


Soft, sandy 




Sand 




Irf- --_ 




:■'"■'■'■ 


(very good 












- 














Black mud(sh 



:-:^~ 


f.VV_'.v_.V ' 

93' 


Mi 




________ 






11 





...JJ 









SECTIONS OF WELLS IN TIA JUANA VALLEY'. 



Well 0101 

ce 



El. 112.0 ft. 



Well 047a 
Surface 
EL 20.60ft. 



. S-r . o.v To 

.Ot.W . 'O.' O 



Hard 
sandyc/ay 



ftPaYS 



s. 



P?«.«v?;C7. 
.O.^-.o.'.o 



AS 



SUPPLY PAPER 446 PLATE XXVll 

Well 077 
Approx. surface 



El. 160.0 ft 

P.'. ?."." o'*'-°' 
O OoOo »' 



n 



& 



Hfeternere 



Alternate clay. 

sand.graue/ 

andboulders 



We 



174 ft. 



If 



6^ 



rhere 
f/ej 

8 



HATION IN VICINI 



o o » O £ o » V 

O 0.0.0,0,0*0 
► . 0,0,0 • » O. 

><*Vooo»'ooa 
"ooOooOooo 

»"V * * "** V ***• " *■ 

Oo O o* o O*o |o 



,0,00 O,o.»»0 



Cemented 33(id 
and grave/, 
.\r*. •• .' :v : yellowish gray 



O.ooOooOO 




20 



Grave/ (good praferj 
C/ay 

Fine sand 



60 



80 



100 



Clay 



"£ 



9 



160 



Sand (best Hta/erJ 
210 ft. 



200 



220 



2-40 



SNYDER & BLACK.N.Y. 



GEOLOGICAI SURVEY 
Well 038 



O i Grave/and 



Cley 

ttff/e HBferJ 
C/sy 



Clay 
andcebbfes 



;. : 



ind(tea/9/y 

v/cemffnfed 
md(noi*a/erJ 



EL 60.0ft. 
- 






C/syJratv/, 
few bau/dere 



Fines and 



Coarse gravel 

Clay 

Coansejrave/ 



NOTE: Descript 

Supplementary c 
are designations 



> of formations 
riptions in parentheses. 



CI 5S.2SM. 



Bou/ders. 
and&atv/ 




Well 047a 
El. 20.60 ft. 

-1-- ~ -A; ''""' " 



\_ "; 



Alternate c/ay, 
andbou/ders 



~-Utt/e h 



, ■ Sand and Arai^J 



eSsSUSS. ELKM. 


VvPij 






- --'-- 




" - . - 


Z^ 


Sandy day 


■il'". 


~=:~ : i 








Vbir/yjood 'w»A?/^§ 



andjrave/ 
sancfcc/ay 



Wv 



sna adobe 



*.;m<Jy ././| 



•--•■"■■-■V% 



SS— SS Hard soil 



■ 

;.;o ".° 



i 0139 

EI.39.6Sfr. 



Well 077 

Approx. surface 

£1.160.0 ft. 






(wtersa/ty 






i BIfK* mudfiAa/eJ 



s 0/&a7r' 

Bou/derSLJ/we/, 
andsand 
(tilt/e wa/erj 



_.::■■ S 



'ave/andfeiv&ou/derj; 




SECTIONS OF WELLS IN SAN DIEGO FORMATION IN VICINITY OF SAN DIEGO BAY. 



WATER IN" THE MAJOR VALLEYS. 



113 



The fill of the main valley has obviously been deposited by the 
main Tia Juana River. Along the margin of the valley, particularly 
opposite tributary canyons from the "mesas," clay and fine wash 
material are intermingled and interbedded with the fill of the main 
valley, as shown by logs of wells 139, 134, O 133, O 131, and 
others (PI. XXVII). In some places accumulations of boulders, 
more or less embedded in clay or mud, have been encountered in 
drilling at the mouths of these canyons. These deposits do not 
extend far out into the valley and are to be expected opposite and 
just below the mouths of tributary canyons. Along the north edge 
of the valley, beginning at a point about a mile southeast of Nestor 
and extending west (PL XX), the valley floor is underlain by bed- 
rocks like those that underlie the "mesa" to the north, as illustrated 
in the geological cross section along the line E-E of Plate XX, figure 9. 



200 



^T 








-% 
















f— *3 1 




— *T 


i «5 






*m 


fcv 






H 














i 


a 




© 


£ 








m, 


^ 




t 




i 










t t 


1 




£ 


I 






SEA 


LEVEL 


•'m 




K=m 




••r 












" 1 






'. ■'•■ .'-- 


Tf-±y 




San D 


ego for 


natioir 


§fcs= 






i"~~*' ■ 


Kiv.V- 




':'.:.:■ :-:'■• 


?..'.-«■'} 


•„'•..:. ?J 


. 1. . 


■y--: 


.,-„r.;. ■» 


mh 




( 


Tertia 


y) 


'"' 




-' - 





• - ' 































































































1,000 



4,000 5,000 

DISTANCE, IN FEET 

EXPLANATION 



9,000 



, Gravel 
(water bearing) 



Poorly assorted gravelly and 
clayey deposits of local origin 

Figure 10.— Diagrammatic cross section of Tia Juana Valley along line F-F, Plate XX. 



Sand , coarse to fine 
(water bearing) 



The entire valley fill is saturated with water, as are also the bed- 
rocks adjacent to the valley on the north and lying below the water 
table in the main valley. All these materials, however, do not 
yield water with equal readiness. The best water-bearing material is 
the layer of gravel underlying the main valley and far enough away 
from the margin to be free from fine material washed in from small 
lateral canyons. This is the formation from which most of the best wells 
in the valley draw their water. The coarser sands that overlie the 
gravels are next in value as water bearers, particularly in the upper 
part of the valley, although good wells drawing from both gravel 
and sand have been obtained west of the north-south road that 
crosses the valley south of Nestor. The most successful wells ob- 
taining water from sand are those around which gravel has been 
worked down so as to increase the intake area and to prevent sand 
from entering and clogging the wells. 

The limits of the deep valley fill of Tia Juana Valley are indicated 
on Plate XX. Wells near the margin.* of this area on the north and 
115536°— 19— wsp 446 8 



114 GKOTJND WATEKS OF WESTEKN SAN DIEGO COUNTY, CALIF. 



south side of the valley may encounter poor water-bearing material. 
Wells out in the main valley, however, will encounter materials such 
as have been described above and are shown in figure 19 and 
figure 10. The logs of 16 typical wells in the deep fill of the valley 
(shown in Plate XXVI) indicate very clearly the different forma- 
tions to be found in various parts of the valley. The water-bearing 
possibilities of the formations underlying the mesa to the north of 
the valley are described under "Ground water on Nestor and Chula 
Vista terraces," page 181. 

Sweetwater Valley. — Prior to submergence Sweetwater Valley was 
very narrow, the bottom being only a few hundred feet wide. In 
general the fill resembles that of Tia Juana Valley. In the lower 
part of the valley the depth of sand is about 60 feet. The layer of 




1300 2,000 

DISTANCE, IN FEET 



EXPLANATION 



2,500 



Sand (waterbearing) Gravel (water bearing) Mud 

Figure 11.— Diagrammatic cross section of Mission Valley along line B-B, Plate XXI. 

gravel and boulders beneath the sand in the bottom of the ancient 
valley exceeds 7 feet in depth. In five wells near Sweetwater Junc- 
tion (O 72) the total depth of the fill was found to be more than 67 
feet but less than 80 feet. In the upper part of the valley the sands 
are much coarser but no logs were obtained of wells that penetrated 
to the gravels. The total depth of the fill is probably less than in 
the lower part of the valley. The limits of the valley fill are shown 
on Plate XX. The best places for wells will be found in areas under- 
lain by coarse sands or by gravels lying at the bottom of the ancient 
valley. 

Mission Valley. — Prior to submergence, Mission Valley had a bot- 
tom width varying from 900 feet just below San Diego Mission (fig. 1 1 to 
1,500 feet at Old Town (fig. 12). Above the mission the width is 
probably less than 500 feet. The floor of the ancient valley was 
formed by the relatively impervious formations that underlie the 



WATER IN THE MAJOK VALLEYS. 



115 



i mesa on either side of the valley, as is shown by the logs of wells 
j K 64, K 93, K 95, K 97, and K 105 (PL XXVIII, fig. 13, and PI. XXI). 
| The valley fill is similar to that of Tia Juana Valley as is shown by 
figures 11, 12, and 13. The gravels lie on the floor of the ancient 
valley, just as in the Tia Juana Valley. The depth of the gravels 
ranges in general from 10 to 20 feet, the depth of the overlying sand 
from about 20 feet at the upper end of the valley to about 65 feet at 
the lower end and the total depth of the fill from about 40 feet at the 
upper end of the valley to nearly 80 feet at the lower end (fig. 13). 
The existence of interbedded clay and other fine material in the valley 
fill opposite lateral canyons is shown by the log of well K 75 near 
Old Town (fig. 12). Deposits of this kind may be encountered in the 
vicinity of other lateral canyons. This material does not yield water 
readily and is to be avoided in locating wells. The bottom of the 























1 




i 




















\ 




••? 




& 




'\ 




^ 




"3 




/> 














f 




A 




I 


* 


* 




k 




M 




m 


■yyyyp/. 




,J 




5) 
1 








% 


s 


$ 




§ 


A 


r 


z 




LEVEL 


ZZZjfy 


^ 


f/Z2 


fr*A 




k 




*5 


s 


iS 




%^XJ% 


/ 


£ o 
o 








■Sa 


°'>tfn 


"m 


&?& 
















■■■M 




< 










(r^ t 


*S 


Z'4 


vm 


W//// 


•m?, 


% 


M 


fe 


//////, 


*M 


y 




ui " l0 ° 












*>) 


s 




















-200 



































1,500 2,000 2,500 

DISTANCE, IN FEET 



EXPLANATION 



3,500 



: ine sand with local deposits 

of boulders and mud from 

tributary streams 



Figure 12.— Diagrammatic cross section of Mission Valley along line A-A, Plate XXI. 

old valley does not, as a rule, lie beneath the middle of the present 
valley, but swings from side to side, its position depending on the 
direction of the current of the ancient stream. Its probable position 
can be determined in some places by a study of the walls of the 
present valley. Where it is not possible to do this, the logs of adja- 
cent wells are the only guide. Wells that do not penetrate the gravels 
at the bottom of the old valley yield small supplies and are not so 
satisfactory as the deeper ones. 

It is much more difficult to determine the best places for wells in 
Mission Valley than in Tia Juana Valley, because the ancient Mission 
Valley was narrower and more winding. The logs of 21 wells in the 
deep fill of Mission Valley, shown in Plate XXVIII, indicate the dif- 
ferent formations to be found in various parts of the valley. The 
limits of the deep valley fill are shown in Plate XXI. It should be 
noted, however, that these limits are considerably wider than the 
bottom of the ancient valley and that all wells put down within these 



116 GKOUND WATEKS OF WESTEElsT SAN DIEGO COUNTY, CALIF. 



r <? t 



7\ m 



en* //*/n 

911 M //•?/*/ 



m 

1 

I 



K** 



C//M //*M 



! 






&& 



"I 



9£M//^U 



J* 

£&$- *9H/I 9 M 



limits will not penetrate the gravels. Other 
wells not shown on Plate XXVIII, of which 
incomplete information was obtained, are 
as follows: Well K 31, 26 feet deep, passes 
through sand and ends in coarse gravel; 
well K 110, 20 feet deep, also passes 
through sand and ends in coarse gravel; 
well K 36, consisting of a group of five 
wells, said to be from 62 to 78 feet deep, 
all end at a bed of cobblestones cemented 
with clay. 

San Dieguito Valley. — San Dieguito Val- 
ley is much shorter than Mission Valley, 
but the conditions in it are similar. No 
well logs were obtained, but it is probable 
that the width of the ancient valley bot- 
tom and the depth and character of the fill 
resemble those of Mission Valley. The 
limits of the deep valley fill are shown ap- 
proximately on Plate XXIII. 

San Luis Rey Valley. — Prior to the sub- 
mergence San Luis Rey Valley was deeper 
than any of the coastal valleys to the south 
and had, in fact, the character of a canyon 
The floor of the ancient canyon and thai 
part of its walls which is now covered by 
valley fill were formed by strata which un- 
derlie the beds that outcrop in the walls 
of the present valley and which are in gen- 
eral similar to these beds. (See pp. 53-66.) 
The width of the old canyon bottom is ap- 
proximately 1,500 feet, as is indicated ii 
the cross section along the line A-A, Plat 
XXV (fig. 14) . The fill resembles generally 
that of the other valleys to the south. A 
the section along the line A-A a mor< 
pronounced segregation of fine material ii 
exhibited than in any other valley. At the 
bottom is a layer of water-bearing grave 
about 20 feet thick; above this is a layer o: 
sand and fine gravel about 70 feet thick 
and above this a layer of fine sand, quick- 
sand, or mud 125 feet thick extends acros 
the full width of the valley. The maxi- 



Well K103 

face 

El. 53.0 ft.* 



Op LOoSrn 



Sff/7 



Muc 



Bou 



Cem 
san 
58' 



II K79-,K64 
Approx_^ : 

El. 15.0 ft. 



Sand a 




Coarse 
andsc 
Compn 



U. S. GEOLOGICAL SURVEY 

Well K94 Well K96 Well K100 



■ER 446 PLATE XXTtn 

Well K34 



,"■ ; : 



^oj 











Sand 




Cemep/ed 


is 



















Corncy-essed 

C :'":■.-:■;. -,J 



'. -'o : 



Coarse gr&re/ 

■■ j .'■ .:/J~\- 



'ir.}\' : i.'l-yj 
Redclay 



Well K79-K64 



in 


"%£?" 









r£^3£€>q Adobe (c/ayj 

o^j bduiders 



El. 44.90. 




'■'G'/.?--'- 




■ ::o' 




O: •.'-•.' 








■•'■ :-'.o.'-. 


Grafelend 
ioutder. (wjterj 

Compressed 


• •P-Vb.:: 


\N ' 





t?2M« 




, ., . 






Sandslone 




Compressed 


__ 



Ca?/-.s<? ja'/za' 



^=te' 



_ _ Co.'rt're^S'rdsi.'f,. //; ' 






:-.■...-, 





":-"'',."" 




t- 1 -' .-, 






_~_ : 


WW.* 


SfeS 












- - - 




O >- ; "'"-<' 
















.-;■-■ 


,ji.i-.i<:..ind 




"■ 












-. : - ■ ■--. 




i _~_"~- 


muddttdfej 


- 1 


'■ -li. ':- 




.~i~ ~ ■ : 
















:S p s- 


%' r3e , 




Mud(shafeJ 


■: -Z~" 


# 61 


"1-I~~ 


f&SL. 


M 






,- :7;± - 







= _--_-^j fi/te <^«» 






SECTIONS OF WELLS IN MISSION VALLEY. 



WATER IN" THE MAJOR VALLEYS. 



117 



mum depth of the fill along this line is 215 feet. (See also tig. 15.) 
The log of well F 12, as recalled from memory by the driller, showed 
bedrock at a depth of about 200 feet overlain by 40 feet of gravel, 
the material above the gravel being sand and silt. Wells west of 
San Luis Rey Mission are reported to have reached a depth of about 
200 feet in the valley fill. Well F 4 is said to have encountered 16 
feet of gravel at the bottom of the fill, the fill being overlain by sand 
and resting on bedrock at a depth of 168 feet. A well 4 miles up 
the canyon, near the mouth of Gopher Canyon, encountered bedrock 
at 58 feet, the material of the fill being sand with two shallow layers 
of gravel down to a depth of 46 feet, followed by a 12-foot layer of 
gravel and boulders. Apparently the fill ranges in maximum depth 
from about 170 feet at the head of the valley just west of the Guajome 
ranch to about 215 feet in the lower part of the valley. The narrow 




3,000 4,000 5,000 

DISTANCE, IN FEET 



EXPLANATION 



8,000 



Fine sand 



Sand and fine gravel Gravel (water bearing) 

in layers (water bearing) 



Figure 14. — Diagrammatic cross section of San Luis Rey Valley along line A-A, Plate XXV. 



width of the old canyon bottom, the resulting small area covered by 
the gravels, and the unusually large proportion of overlying fine 
material render it very difficult to place successful wells. The only 
wells from which a good yield is assured are those that penetrate to 
the gravels. The same methods can be followed in determining the 
position of the channel as were suggested for Mission Valley, but 
owing to the greater width of the modern valley, however (PL XXV), 
the problem is more difficult than in Mission Valley. 

Santa Margarita Valley. — Although Santa Margarita Valley was 
not carefully studied, conditions in it are supposed to be similar to 
those in San Luis Rey Valley. Wells in this valley are said to reach 
bedrock at a depth of about 200 feet, a fact indicating that the depth 
of the fill is about the same as in San Luis Rey Valley. Inspection 
of the limits of the valley fill as shown on Plate XXV suggests that 
the bottom of the old canyon is little if any wider than in that valley. 



118 GROUND WATERS OF WESTERN" SAN DIEGO COUNTY, CALIE. 



SAN LUIS REY VALLEY 



Well C 2 

Surface elevation 

422.67 ft. 



Well F 15 

Approximate 

surface elev. 

32 ft. 



Well FI4 

Approximate 

surface elev. 

32 ft. 



UPPER SWEETWATER VALLEY 

Well L 102 

Approximate 

surface elev. 

540 ft. 



40 



■"••' *'■'. 


i'y'Q 


•5Q: 


■'.;'■■ V 




£> : f: 


£>•• 


o ■'• , 


.o 


>,° ° 




£x 


^o 


■'.■'''''- 


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1 •••<— 






o 


rv 
















'*• 


o 







Sand, gravel, 
and boulders 



63 feet 



Sand 



Sandy clay 



Sand (water) 



Coarse sand 
(water) 



Clay 
195 feet 



Note.- Descriptions of formations are 
given as stated by driller or owner. 



Fine sand 
andsilt 



Medium to 
coarse sand 



Coarse sand and 
a few pebbles 



Coarse sand 
and gravel 



Hard sandstone 
230 feet 



Sandy surface 
soil-,some coarse 
sand 

Very coarse §ravel; 
boulders 



:. Coarse sand 
(water) 

J 50 feet 

I 



Figure 15. — Sections of wells in upper San Luis Rey and upper Sweetwater valleys. 



WATER IN THE MAJOR VALLEYS. 119 

HIGHLAND VALLEYS. 

The major river valleys of the highland area are ancient valleys 
which at some stage of their geologic history were mountain canyons 
and which have been filled to their present levels with alluvial debris 
deposited by the streams that enter and traverse them. The ancient 
canyons were cut into the granite rocks that underlie the modern 
fill. These canyons were more or less winding and of varying width. 
They were, in fact, similar to the many canyons that can be seen 
to-day in the highland area. The filling of the ancient canyons 
resulted from diverse causes, and they will be described separately. 

Upper Sweetwater Valley. — On the west upper Sweetwater Valley 
is limited by the chain of hills, composed of porphyry, which extends 
along the margin of the coastal plain from the international boundary 
almost to the San Luis Key River. The porphyry is exposed in the 
present bed of Sweetwater River in the canyon at the Sweetwater 
dam, where the stream cuts through the formation, but above the 
canyon the old rock bed of the stream is covered by valley fill. No 
logs of wells that penetrate the entire thickness of the fill have been 
obtained in this valley. Well L 102 (fig. 15) passed mostly through 
coarse water-bearing sand, and reached a depth of 50 feet without 
encountering bedrock. The four wells designated L 100 are spaced 
100 feet apart in a line across the channel of Sweetwater River. 
They are 45 feet deep and only the well nearest the hill on the south 
reached bedrock. The material was coarse sand and silt in layers. 
Well L 41 reached a depth of 34 feet in coarse sand and gravel with- 
out reaching bedrock. The 18 wells designated P 24 are 38 feet in 
average depth, but no information was obtained as to bedrock. So 
far as known, the fill consists chiefly of fine and coarse sand with 
occasional layers of fine gravel. The coarse sand predominates, 
particularly in the upper part of the valley. The total depth of fill 
is probably not more than 80 feet at the upper end of the valley and 
probably much less toward the lower end, below Jamacho. 

Upper San Diego River valley. — The geologic history of upper San 
Diego Valley is probably somewhat similar to that of upper Sweet- 
water Valley. (See fig. 13 and PL XXIX.) An interesting fea- 
ture of the fill is a deposit of clay, merging upstream into gravel 
and boulders more or less cemented with clay, that underlies the 
sand for the first 5 miles above the Old Mission dam. This deposit 
suggests the former existence of a body of still water behind the 
range of porphyritic rocks, into which the river discharged. The 
coarser material transported by the river would naturally be depos- 
ited at the upper end of the lake and the finer material would be 
carried out and spread over the lake bottom. The filling of the lake 
and subsequent aggradation would result in the accumulation of 



120 GKOUND WATEKS OF WESTEKN SAN DIEGO COUNTY, CALIF. 

coarse debris over the surface formerly occupied by the lake, while 
the fine material, held in suspension by the flowing water, would be 
carried on through the basin. This process would ultimately build up 
alluvial debris to the new grade of the river under the changed con- 
ditions. This action is suggested by the profile of the valley fill as 
shown by figure 13. The water-bearing part of the valley fill — the 
sand and fine gravel overlying the clay and cemented gravel — varies 
in depth from a few feet at the lower end of the valley to more than 
100 feet above the mouth of San Vicente Creek, opposite Lakeside. 
Four drilled wells, designated L 74 (PI. XXII), pass through coarse 
sand and gravel. One of these wells is said to be 1 1 1 feet and another 
129 feet deep. Three wells designated L 73 are about 45 feet deep 
and end in coarse sand. Wells L 7 a to L 7 d are 70 feet deep and 
end in coarse sand. Five wells designated L 69 are reported by the 
driller to be 80 to 85 feet deep and to end in coarse sand. The logs 
of other wells are shown on Plate XXIX. The sand becomes finer 
toward the lower end of the valley, particularly below Riverview 
Station, and in some wells considerable trouble is caused by clogging 
of screens with fine material. 

The character and depth of material in the fill of Foster Valley along 
San Vicente Creek are indicated by the following information fur- 
nished by owners or drillers of wells. The iive drilled wells designated 
L 60 (PI. XXII) end in clean coarse sand mixed with gravel and at 
an average depth of 95 feet. Well L 61, 78 feet deep, passes through 
40 feet of sand and gravel, 10 feet of black mud or silt and 28 feet 
of sand, gravel, and boulders. Well L 62, 77 feet deep, penetrates 
about 30 feet of black mud similar to that in well L 61. WeH L 64, 
78 feet deep, passes through 40 feet of silt and sand, fine to coarse, 
merging into boulders 8 to 10 inches in diameter at the bottom. 

San Pasqual Valley. — The history of San Pasqual Valley is similar 
to that of the upper Sweetwater and San Diego river valleys, 
although it affords no indications of the existence of such a body of 
still water as may have existed in upper San Diego Biver valley. The 
depth to bedrock has not been determined, as few if any of the wells 
in the open valley reach the granite. The following wells, whose 
location is shown on Plate XXIV, indicate the character of the fill. 
Well H 30, 150 feet deep, passed through sand and silt to a hard 
boulder or bedrock which was too hard to drill with the sand bucket. 
The depth of the fill in the main valley probably exceeds that of the 
tributary canyon in which this well is located. The material 
encountered was much finer in this well than in the main valley 
and the well has never been used on account of its small yield. 
Well H 33, 60 feet deep, penetrated sand and gravel. Well H 35, 
86 feet deep, passed through sand, gravel, and silt, with boulders at 



WATER-SUPPLY PAPER 446 PLATE XXIX 



20 



40 



60 



80 



76 



Z0 



40 



eo 



80 



100 



120 



140 



160 



Well L80 Wei! L81 
Approximate surface 



El. 390.0 ft. 



El. 380.0 ft 



£&;? 



ttz.*:, 



■0 



Silt 



Alternate layers 
siltandsand 



Black clay- 
Gravel and 
boulders 
(water) 



Fi Tie sand and 
sediment 




Fine blue sand, 
clean 



20 



40 



60 



80 



Well K118 
Surface 

E1.3l7.5ft. 



Well K116 
Approxjsurface 

El. 312.0 ft. 



'dmarl 
clay) 



Sand 
(water) 



Marl 
(clay) 



Sandy soil, §ra vel, 
cobbles (dry) 

Sand, cobbles 
(■water) 



Blue clay 
35' 



>pth 



20 



40 



60 



80 



100 



120 



140 



—1 160 



rr..\ ('!■; x.vix 






" -\-.Jr~ ?yefio> 
k-rV^y^ gravel 
Decomposed 



gmM£gf~&lJ™ 






■'■■• -,;.-<? ?/nf 



! ir ! 



Coarse red sand 

Coarse sand, pebbles 

Cemented sand 
Sand and pebbles 
Fine sand and gravel 
(good water; 

r Sand and gravel 
Decomposed granite 



lae sand and cobbl 
i^Brovmsand 



isoL- 



— _i— ~ Sand and 



-:>..■ ,-r, '.-. 



El 312 ft 




HI 


;-> ; ^ 



and, cobbles 
Blue clay 



. ui'i'l /'. S\N mrco ltl\ Kit \ \I.U'\. 



WATER m THE MAJOR VALLEYS. 121 

the bottom. Well H 2, 40 feet deep, passed through sand which 
was coarse at the bottom. Well G 31, 77 feet deep, passed through 
6 feet of clay and then through sand and gravel, with large boulders 
at the bottom. Well G 30, 52 feet deep, penetrates sand, silt, and 
gravel, the formation at the bottom being coarse sand and boulders. 
Well G 29, 80 feet deep, encountered silt for the first 10 feet, very 
coarse sand for 30 feet, coarse to medium sand rather sticky and 
yielding water slowly for 30 feet, and decomposed granitic bedrock 
for the last 10 feet. Wells G 31, G 30, and G 29 are all in a tributary 
valley, but their records give information in connection with the 
probable depth of the main valley. Well G 33 is 93 feet deep and 
passed through silt and sand, the latter being coarse at the bottom. 
Wells G 35 and G 34 are 45 feet deep and pass through sand and 
gravel. The sand of the main river valley yields water readily. 

Upper San Luis Bey Valley. — The fill of upper San Luis Key Valley 
has unbroken connection with the fill of the coastal valley (PL XXV) 
and evidently occupies a deeper valley or canyon which was formerly 
a continuation of the ancient coastal valley. Filling has resulted from 
submergence. Well logs show that the depth of the fill in the canyon 
below Bonsall is 60 feet. Well C 41 is 75 feet deep and passes through 
coarse sand and fine gravel. According to the driller the eight wells 
designated C 8 encountered bedrock at 60 feet and penetrated sand 
with boulders at the bottom. Well C 2 (fig. 15) encountered coarse 
gravel and boulders to a depth of 63 feet without reaching bedrock. 
Where the present valley is wide the best water-bearing material 
would probably be found near the old channel. 

POROSITY. 

The voids between the particles of silt, sand, and gravel composing 
the valley fill of the principal river valleys contain the stored ground 
water. The percentage of porosity varies in different materials and 
even in different parts of the same material, according to the relative 
size and arrangement of the individual particles. Experiments made 
by the writer on 36 samples from the fill of the major river valleys of 
San Diego County, the material varying from coarse sand to silt, 
indicated total voids expressed as per cent by volume as follows: 
Coarse sand, 39 to 41 per cent; medium sand, 41 to 48 per cent; fine 
sand, 44 to 49 per cent; fine sandy loam, 50 to 54 per cent. The 
average porosity of all 36 samples was 45.1 per cent. The classi- 
fication of materials is that used by the Bureau of Soils of the 
United States Department of Agriculture. These percentages repre- 
sent the porosity of the material under natural condition as to size 
and arrangement of grains. The method of determining porosity 
was as follows : 



122 GROUND WATERS OF WESTERN" SAN DIEGO COUNTY, CALIE. 

A pit was dug to the level from which it was desired to take the 
sample, a part of the bottom being excavated to a further depth of 
about a foot so as to leave a vertical face; a metal cylinder 5f inches 
in inside diameter and 9 inches long, the lower edge being beveled 
from the outside so as to make a cutting edge, was pressed down 
vertically, cutting out a core of undisturbed material; the material 
was then carefully dug away from the front of the cylinder and a 
stiff sheet of metal pushed under to cut off the sample at the bottom 
of the cylinder ; the metal plate and cylinder were then removed and 
the top of the sample was leveled off. This method gave a- sample of 
the known volume as it existed in its natural state. The sample was 
then oven-dried and the specific gravity of a selected portion deter- 
mined. The porosity was then computed by the following formula: 

p= 100(1-!) 

in which P = Porosity expressed in percentage 

w = Specific gravity of the dried sample 

W = Average specific gravity of the minerals comprising the 
sample. 

A certain proportion of the moisture that occupies the voids of any 
saturated porous material does not readily drain out, even when the 
zone of saturation has fallen below the depth from which the capillary 
rise of water is rapid. This moisture can not be extracted by pump- 
ing nor does it represent water that drains out and is replenished 
during the natural fall and rise of the water table. To determine the 
water-retaining capacity of various valley-fill materials, six experi- 
ments were made after the annual summer lowering of the water 
table had taken place. The water-retaining capacity was found to 
range from 6 to 10 per cent in the coarse, medium, and fine sands, but 
no finer materials were examined where the depth to the water table 
was great enough to enable the field capacity to be determined with 
certainty. Etcheverry, 1 quoting from Widtsoe's extensive experi- 
ments, gives the water-retaining capacity of sandy loam as 14 J per 
cent by weight, which is equal to about 22 per cent by volume, and 
this percentage can be considered as representing roughly the condi- 
tion in sandy loam soils of the major river valleys under consideration. 
The total volume of water that might be drained from the valley fill 
by the slow lowering of the water table can be estimated as ranging 
from about 33 to 37 per cent by volume. Such complete drainage, 
however, requires considerable time, and the relatively quick drainage 
resulting from the artificial lowering of the water table by pumping 

1 Etcheverry, B. A., Irrigation practice and engineering, vol. 1, p. 4, New York, McGraw-Hill Book Co., 
1915. 



WATER IN THE MAJOR VALLEYS. 123 

undoubtedly represents the extraction of far less of the total water 
content. In practice the proportionate volume that could he ex- 
tracted from the valley fill of the major valleys probably does not 
exceed 20 to 25 per cent. In other words, a general lowering of the 
water table of 1 foot by pumping would represent, on the average, an 
extraction of 65,000 to 81,000 gallons from each acre of valley fill. 

The method used by the writer for determining the water-retaining 
capacity was as follows: Pits were sunk to the ground water at 
points selected so as to give differing distances to the water table and 
differing types of material. Samples of the material were taken at 
intervals of a foot from the surface down to the water table, as 
described above for porosity samples. The initial weight of the 
samples with the contained moisture was ascertained immediately 
after removal from the pit, and the dry weight was obtained after 
oven drying; the difference in weight, representing the retained 
water expressed as a percentage by volume, gave the percentage of 
retained water by volume when divided by the initial volume of the 
sample. This percentage was found to vary at different distances 
above the water table. The maximum was at the water table, where 
the material was saturated and the percentage of initial moisture was 
practically equal to the total porosity of the material; the minimum 
occurred near the surface of the ground but at a depth sufficiently 
great to be beyond the range of evaporation. It was found that by 
representing the data graphically, the water-retaining capacity of 
samples ranging from coarse to fine sand could be approximately 
ascertained by inspection. The zone of saturation was too near the 
surface, however, to enable this to be done with finer materials. 

The volume of water represented by the annual rise and fall of the 
zone of saturation was computed from these same diagrams. For the 
average annual fluctuation of approximately 3.5 feet, it was found 
that the effective porosity — that is, the difference between the total 
porosity and the water-retaining capacity — ranged from an average 
of 41 per cent for sand of differing grades and with differing depths 
to the water table, to 16 per cent for fine sandy loams. The average 
for the six typical conditions studied was 34 per cent. 

THE WATER TABLE. 
FORM AND SLOPE. 

The water table is the surface below which the voids of any extended 
body of porous material are completely filled with water. Although 
ft the voids above the surface usually contain either capillary or hydro- 
scopic water, such water occupies only a portion of the total void 
space. The water table of an underground reservoir corresponds 
to the surface of an ordinary lake or reservoir. It is seldom a level 



124 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

surface, however, as is an ordinary water surface, but has an appre- 
ciable slope which varies at different places and at the same place at 
different times of the year. In general, in the major valleys, it has 
the slope and to some extent the form of the ground surface, although 
important differences exist. Its depth below the surface in the major 
valleys of San Diego County varies at different times of the year and 
in different parts of the valleys from a few inches to as much as 20 
feet, but the average depth is close to 5 feet. The position of the 
water table is represented by the level of standing water in wells. 

Knowledge of the position, slope, and fluctuation of the water table 
is essential in the study of ground-water problems. To obtain such 
information the writer selected 87 wells in the major river valleys 
of San Diego County, and made observations of the depth to the water 
level at intervals of one month or less from September, 1914, to 
August, 1915. In upper Sweetwater Valley the Sweetwater Water Co. 
cooperated in making observations on the selected wells. Observa- 
tions were also made by the writer at 34 wells that had been more 
or less regularly observed since 1912 by the United States Geological 
Survey, the Vulcan Land & Water Co., and the Cuyamaca Water Co. 
Observations were also made at a well observed prior to September, 
1914, by Mr. Lebert, of San Diego. The total number of wells 
observed during the season 1914-15 was 122. The location of each 
of these wells is shown on Plates XX to XXV. Wells were selected 
which were representative of ground-water conditions in the vicinity 
and which, with other wells, would give comprehensive information 
in regard to the water table over whole valleys. Wells that were not 
likely to be influenced by abnormal local conditions, such as pumping 
or irrigation, were preferred to others. A permanent bench mark 
was chosen at each well from which vertical measurements to the 
water surface could be made with a steel tape. The accurate eleva- 
tion above sea level of all bench marks was determined instrumentally 
from the nearest bench mark of the United States Geological Survey, 
and all water-level observations were referred to sea level. 

A complete list of wells in which a series of water level measure- 
ments were made is given by number, in Table 45 (p. 209), together 
with the location, owner's name, class of well, depth of well, elevation 
of ground surface, description and elevation bench mark, geologic 
source of water, and local conditions of surface and vegetation. 
This table includes records of all wells observed by the writer, not only 
in the fill of major valleys but also in other water-bearing formations. 
The column headed " geologic source of water" designates the forma- 
tion from which the well derives its water, the terms "deep valley 
fill" and "shallow fill or major river valleys" both applying to wells 
in the major river valleys. These terms are used to distinguish the 



WATER IN THE MAJOR VALLEYS. 



125 



deeper parts of the fill or major river valleys, in which the best water- 
bearing formations occur, from the shallower parts in which the fill 
is thin and contains but little gravel or coarse sand. The approximate 
limits of each of these formations is shown on Plates XX to XXV. 

The individual observations at all record wells are too numerous 
to be presented in this report, but summaries and typical records 
are given in Table 30, covering observations during the period 
September, 1914, to August, 1915, and Table 31, which covers the 
period March, 1912, to August, 1915. The fluctuations are shown 
graphically in Plates XXX to XLII and figures 16 to 18. 



126 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



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WATER IN THE MAJOR- VALLEYS. 



127 



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130 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



Table 31. — Summary of observations of water 
[For summary for wells observed 









Eleva- 
tion of 
ground 
surface 
(feet). 


1912 


1912-13 


Well 
No. 


Geologic source 
of water. 


Highest level 
observed. 


Lowest level 
observed. 


Highest level 
observed. 




Date. 


Eleva- 
tion 

(feet). 


Date. 


Eleva- 
tion 
(feet). 


Date. 


Eleva- 
tion 
(feet). 


L90... 


Deep fill of major 


317. 50 
394. 00 
412. CO 
414. 00 
408.44 
5.70 
54.00 

270.00 

410. 00 
325. 00 

318. 8J 
354. 0.) 






Sept. 25, 1912 
Oct. 18,1912 
do 


308. 80 
386. 60 
400. 30 
405.55 


Apr. 12,1913 
do 

do 

Dec. 27,1912 


311.98 
387. 60 
402. 30 
406. 87 


L76... 


do 

do 

do 

do 

do 

do 

Shallow fill of 
major valley... 

Deep fill of major 






L65... 






L 67. . . 






Oct. 19,1912 


L68-b. 






K63o.- 






Nov. 23,1912 
Dec. 27,1912 

June 25,1912 

Nov. 13,1912 
Dec. 27,1912 

Jan. 28,1913 


5.38 
53.46 

272. 40 

406. 25 
314. 45 

312. 15 


Apr. 14,1913 
Apr. 12,1913 

Jan. 28,1913 

May 12,1913 
May 15,1913 

Apr. 12,1913 
May 15,1913 

Apr. 12,1913 
Apr. 10,1913 
Mar. 13,1913 

do 

do 

June 16,1913 

Mar. 15,1913 

do 

.....do 

do 


6.01 
54.27 

272.64 

407. 42 
315. 86 

313. 08 
338. 61 

403. 90 
416.21 
413. 93 

381. 90 
377. 71 
343. 10 

430. 43 
430. 87 
430. 83 
431.45 


K 107b. 






K 114c. 






L70/. 






L 92. . . 








K117.. 


Fill of minor 


L 110 








L66... 


Deep fill of major 


412. 00 
419. 14 
420.28 

381.97 
379.23 
(350. ) 

438.20 
437.80 
437. 70 
437.00 
498.40 
313.00 
265.00 

111.50 

79.30 

66.90 
63.55 
54.00 
47.82 
41.00 
32.10 
26.80 
12.22 






Nov. 13,1912 
Sept. 24,1912 
July 13,1912 

Sept. 24,1912 
do 


402. 59 . 

413.17 

407.78 

380. 05 
375. 96 
338. 66 

427. 80 

427. 85 

428. 05 
428. 70 


H5 


do 






H 32 






H31.. 


Deep fillof major 






HI .. 


do 






G32... 






Jan. 20,1913 

Oct. 9, 1912 

do 

do 


L7-a. 


Deep fill of major 






L7-b. 
L 7-c. 


do 

do 

do 

do 

do 

do 

Fillof minor val- 
ley 






L7-d. 






July 22,1912 


L75». 






CIO.. 
C9.... 
B 10.. 


Apr. 19,1912 
Apr. 12,1912 

Apr. 15,1912 

Apr. 19,1912 

May 21,1912 
do 

Apr. 15,1912 
Apr. 19,1912 
Apr. 13,1912 
Apr. 19,1912 
Apr. 13,1912 


307. 43 
264. 64 

102. 03 

70.96 

62.88 
58.99 
55.38 
42.16' 
39.57 
28.68 
24.59 


Sept. 20, 1912 
do 

Jan. 2,1913 

Jan. 18,1913 

do 

do 

Dec. 18,1912 
Oct. 31,1912 
Sept. 22, 1912 
Oct. 31,1912 
Sept. 22, 1912 


306. 14 
261.34 

97.61 

65.59 

55.94 
53.69 
52.15 
40.48 
35.66 
26.61 
21.41 


Feb. 20,1913 
Jan. 2, 1913 

Mar. 8, 1913 

do 

Apr. 8,1913 
do 

Mar. 21,1913 
.-,.-do 

Mar. 8, 1913 

Apr. 8, 1913 
do 


306. 69 
263. 85 

101. 19 

70.54 

62.94 
60.30 
54.73 
41.40 
3G.77 
27.98 
23. 20 


Bll.. 

Fa/.. 


Shallow fill of 

major valley. . . 

Deep fill ol major 


F20/.. 
F19... 
F17... 
F16... 
F3... 
F13.-. 
F 11... 


do 

do 

do 

do 

do 

do 

do 


:::: 





















a U. S. Geological Survey gaging station at San Diego (Old Town). 

b In river channel. 

c U. S. Geological Survey gaging station at Mission dam. 

d Continually. 

e Rising. 

Note. — Observations by U. S. Geological Survey in cooperation with Volcan Land & Water Co. 
and Cuyamaca Water Co., except as otherwise noted. For rise and fall each year, see Table 33. 



WATER IN THE MAJOR VALLEYS. 



131 



level, in feet, at wells in San Diego County, 1912-1915. 
during 1914-15, see Table 30.] 



1913-14 



1914-15 



Lowest level 
observed. 



Highest level 
observed. 



Lowest level 



Highest level 
observed. 



Date. 



Elevation 
(feet). 



Date. 



Eleva- 
tion 
(feet). 



Date. 



Eleva- 
tion 
(feet). 



Date. 



Eleva- 
tion 
(feet). 



Oct. 30,1913 

..-.do 

Oct. 1,1913 
Oct. 30,1913 



Oct. 29,1913 

Apr. 12,1913 

Aug. 24,1913 
Jan. 21,1914 

do 

July 23,1913 

Oct. 30,1913 
Oct. 29,1913 
July 28,1913 

Oct. 29,1913 

do 

Aug. 20,1913 

Oct. 30,1913 

do 

do 



Dec. 12.1913 
June 13,1913 
July-Aug.1913 

Dec. 9,1913 

....do 

....do 

....do 

....do 

Sept. 29, 1913 
Aug. 19,1913 
Nov. 1,1913 
Sept. 29, 1913 
Dec. 9, 1913 



385.15 
399.38 
404. 15 
398. 13 



Mar. 5, 1914 
May 12,1914 
Mar. 5,1914 
....do 



52.37 

272.49 

404.59 
313.46 

310. 61 
335.56 

400.96 
412.50 
409.15 

379.52 
375.33 
337.99 

426.48 
426. 63 
427.13 



Mar. 3,1914 
(d) 



May 
Mar. 



1,1914 
6,1914 



May. 13, 1914 
Apr. 4, 1914 

Apr. 20,1914 
Feb. 27,1914 
do 

.-..do 

Mar. 27,1912 
Mar. 27,1914 

Mar. 3, 1914 

do 

do 



479. 42 

305. 92 

(261.00) 

97.35 

65.26 

55.44 
53.23 
51.30 
39.96 
34.53 
26.42 
21.24 
13.20 



July 1, 1914 
Mar. 1, 1914 
Jan. 23,1914 

May. 9,1914 

Mar. 9, 1914 

May 9,1914 

do 

Mar. 9, 1914 
Feb. 28,1914 
Jan. 30,1914 
Mar. 9, 1914 
Jan. 30,1914 
....do 



389.65 
402.34 
407.55 
401.68 



55.25 
(<*) 

407.40 
315.37 

317. 25 
337. 14 

403.60 
416. 43 
417.12 

382.06 
378. 12 
344.96 

430.81 
431. 19 
431.69 



488. 42 
307. 60 
263.82 

101.53 

70.73 

62.90 
60.99 
55.28 
43.02 
39.13 
29.44 
24.89 
15.46 



Oct. 13,1914 
do 

Nov. 10,1914 

do 

do 

Nov. 7,1914 

Oct. 13,1914 

(') 

Nov. 10,1914 
Dec. 7, 1914 

do 

Jan. 17,1915 

Dec. 7,1914 
Oct. 14,1914 
do 

do , 

do , 

Jan. 25,1915 

Oct. 23,1914 

do 

do 

do 

Jan. 16,1915 
Aug. 19,1914 
do 

Nov. 25,1914 

Jan. 9, 1915 

do 

do 

Dec. 9,1915 
Nov. 13,1914 

.....do 

Dec. 14,1914 
Aug. 19,1914 
Nov. 14,1914 



313.60 
385. 25 
398.90 
404.01 
397.76 
4.84 
52.32 

(*) 

404.45 
313. 16 

311.82 
336.20 

400.55 
412.91 
408.26 

380.07 
375. 73 
338.39 

424.70 
424.71 
426.71 
427. 00 
479. 22 
305.91 
261.50 

97.53 



56.35 
54.04 
52.25 
40.69 
36.07 
26.50 
21.19 
13.45 



May 3, 1915 

do 

Mar. 11,1915 

do 

Feb. 13,1915 
Feb. 12,1915 
May 3, 1915 

Feb. 13,1915 

Feb. 3,1915 
Mar. 10,1915 

do 

July 5, 1915 

Mar. 11,1915 
Feb. 25,1915 
Feb. 1,1915 

May 4,1915 
do 

(h) 

May 4, 1915 

do 

do 

Feb. 3, 1915 
May 10,1915 
Feb. 24,1915 
May 5, 1915 

May 31,1915 

Feb. 24,1915 

May 5,1915 

do 

....do 

Feb. 24,1915 
Feb. 5, 1915 
Feb. 24,1915 
do 



315.01 
391.62 
405.31 
408.52 
403.29 
10.31 
57.57 

276.73 

409.08 
317.31 

318.98 
340.54 

405.82 
416. 99 
418.06 

382.17 
378.77 
(ft) 

431.70 
431.99 
432. 17 
432.57 
491. 42 
308.24 
264.82 

101.36 

72.05 

63.30 
59.77 
56.08 
44.18 
40.93 
30.14 
26.14 



/ TJ. S. Geological Survey gaging station at 
g Well affected by pumping, 
ft Record ended Jan. 25 ,1915. 
i Observed by Mr. Lebert. 
i Affected by ditch. 



132 

In addition to the above data, contours of the water table, or lines 
connecting all points at which the ground water has the same eleva- 
tion, have been drawn from the original observations to show the 
position of the water table in Mission Valley October 22, 1914, and 
February 18, 1915 (PL XXI), and in Sweetwater, Otay, and Tia 
Juana valleys and the intervening low terraces January 6 and March 
1, 1915 (PL XX). 

The ground-water profiles and cross sections (Pis. XXX to XXXV, 
fig. 9), and the contours of the water table (Pis. XX and XXI), show 
that in the major river valleys the water table slopes downstream, 
with a slight tendency outward from the stream channel toward the 
edge of the valley during the period of river flow, but with practically 
no transverse slope at other times of the year and particularly not 
during the last part of the year. 

FLTJCTXTATIONS OF THE WATER TABLE. 

The water table at any point is constantly either rising or falling. 
The rate of rise or fall varies widely at different places and times, 
depending on the position of the place with respect to the sources or 
outlets of the ground water and the rapidity of the accretion and 
depletion of the supply. The fluctuation of the water table is an 
index to the relative rates of supply and loss of ground water and in 
this respect corresponds to the rise and fall of water level in a reservoir. 

The water table in the fill of the major valleys fluctuates annually, 
and this fluctuation was observable in all the wells studied during 
the years 1912 to 1915. The annual fluctuation is the result of the 
annual variation in rainfall, stream flow, evaporation, transpiration, 
and other conditions affecting ground-water levels. The water table 
reaches its lowest stage during the months October to January pre- 
ceding the first storm heavy enough to produce run-off. The average 
date of minimum level in 1914 was November 7 (Table 32), and this 
is nearly the average date for other years. Coincident with the first 
heavy storm producing run-off, usually occurring in January (Table 
34), water levels rise more or less sharply, reaching their maximum 
level during the months January to April. The average date of 
maximum level in 1914 was March 19 (Table 32); taking all seasons 
into consideration April 1 is probably about the average. From the 
date of maximum level to the last part of the year levels are grad- 
ually lowered, the rate of lowering being greatest from April to 
August. The average fluctuation for the year 1914-15 at all obser- 
vation wells in the major valleys was 4.70 feet (Table 32). That 
this range is greater than the annual average is indicated by the 
records at wells in upper San Diego and San Luis Rey Eiver valleys 
during the period 1912 to 1915 (Table 33). Judging by the condi- 
tions in these two valleys, the average annual fluctuation of the 
water level in the major valleys is about 3.6 feet. 



c 



iU 



tE 



U. & GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 446 PLATE XXXI 




SECTION' ACHOSS MISSION VALLEY AT OLD TOWN PUMPING PLANT, SHOWING PROFILES OF WATER TABLE IN DIFFERENT SEASONS OF THE YEAR, 1!)H-1!)1.5. < Red line A -A . Plate XXI I 



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distance: from ROAD IN FE£7 
ECTION ACROSS UPPER SAN DIEGO RIVER VALLEY AT MONTE PUMPING PLANT, SIlOWlNi 



FLUCTUATIONS OF WATER TABLE, SEASON 
XXII ) 



14-1915, AND PLAN OF PUMPING PLANT. 



WATER-SUPPLY PAPER 446 PLATE XXXR^ 



TIA JUANA 




...June 7, 1915 
March S, /S/5 
■August f, 1915 
■February 9, /S/5 
October 12.1914 
January 21, 19/5 



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s'.\ VALLEY, SHOWING FLUCTUATIONS OF WATI.K TABLE, SEASON L814-101S. 
(Red line B-B, Plate XX 



WATER IN THE MAJOR VALLEYS. 



133 



Table 32. — Annual range of fluctuation of water level in record wells in San Diego 

County, 1914-15. 





Valley. 


Num- 
ber of 
wells 
ob- 
served. 


Annual range of fluctuation. 


Geologic source of 
water. 


Average date 

of maximum 

level. 


Average date 

of minimum 

level. 


Maxi- 
mum 
in any 
well. 


Mini- 
mum 
in any 
well. 


Aver- 
age in 
all 

wells. 


Deep fill of major 
valley. 
Do 




9 

8 
9 
17 
22 
5 
14 


Apr. 11,1915 

Apr. 4,1915 
Feb. 21,1915 
Mar. 22,1915 
Feb. 22,1915 
Mar. 22,1915 
Mar. 25,1915 

Mar. 19, 

Feb. 28,1915 
Feb. 27,1915 

do 

Apr. 16,1915 


Nov. 25,1914 

Oct. 25,1914 
Nov. 11,1914 
Nov. 12, 1914 
Nov. 13,1914 
Oct. 20,1914 
Nov. 4,1914 

Nov. 7, 

Oct. 22,1914 
Jan. 7,1915 

do 

Nov. 1,1914 


Feet. 
13.69 

8.50 

6.26 
12.20 

8.01 
10.12 

8.11 


Feet. 
3.72 

1.54 
.93 
1.41 
2.33 
2.10 
1.19 


Feet. 
7.08 


Upper Sweetwater 
Lower Sweetwater 
Upper San Diego. . 
Lower San Diego. . 

San Pasqual 

San Luis Rey . 


4.11 


Do 


2.71 


Do 


5.57 


Do 


5.16 


Do 


4.58 


Do... 


3.61 














4.69 




Otay 










Fill of minor valleys 
Do 


5 
1 

1 
4 


8.75 
2.19 
9.45 
5.54 


3.99 
2.19 
9.45 
5.33 


6.91 


Murpliy Canyon. . 
Murray Canyon . . . 
Miscellaneous 


2.19 


Do 


9.45 


Do..... 


5.46 














6.18 








Apr. 11,1915 
May 21,1915 

Mar. 27,1915 
July 1,1915 

July 30,1915 
Mar. 31,1915 


Dec. 16,1914 
Nov. 18,1914 

Oct. 31,1914 
Nov. 7,1914 

Oct. 29,1914 
Nov. 7,1914 








Residuum (decom- 
posed granite). 


10 


11. 00 


3.43 


6.31 


Vicinity of Nestor. 

Vicinity of Otay.. 
Vicinity of Chula- 

vista. 

National City 

Vicinitv of Old 

Town. 




San Diego forma- 
tion less than 200 
feet below sea 
level. 
Do 


11 

10 
5 

1 
1 


5.83 

8.76 
.82 

.93 
2.34 


1.38 

.58 
.17 

.93 
2.34 


2.59 
4.32 


Do 


.47 


Do 


.93 


Do 


2.34 














2.76 






1 











Table 33. — Annual range of fluctuation, in feet, of water level in record wells in San 
Diego County, 1912-13 to 1914-15. 



Upper San Diego River Valley (deep valley fill.) 



Well No. 


Lowering 
of 1912. 


Rise of 
1912-13. 


Lowering 
of 1913. 


Rise of 
1913-14. 


Lowering 
of 1914. 


Rise of 
1914-15. 


Average 
lowering. 


Average 
rise. 


L 75 








9.00 


9.20 


12.20 
5.57 
5.46 
7.28 
7.00 
4.63 
4.51 
5.27 
6.41 
5.53 
6.37 


9.20 


9.00 


L 7-d 




2.75 
2.78 
3.02 
2.63 
1.17 
1.32 
1.31 
2.00 




4.16 


L 7-c 




3.70 
4.24 
3.95 
2.83 
2.72 
2.94 
2.92 


4.56 
4.56 
4.33 
2.81 
3.40 
2.64 
2.96 
3.55 
4.50 


4.98 
6.48 
6.11 
2.95 
3.54 
3.05 
3.44 
3.92 
4.40 


4.34 
5.36 
5.03 
2.89 
3.13 
3.00 
3.18 
3.92 
3.43 


4.27 


L 7-b 




4.95 


L7-a 




4.65 


L 70 




2.87 


L 67 




3.08 


L66 




3.07 


L 65 




3.79 


L 68-b 




4.54 


L 76 




1.00 


2.45 


3.91 








Average 




2.12 


3.29 


4.23 


4.81 


5.97 


4.35 


4.22 








Lower San Diego River 


valley (deep valley fill). 






K 107 




0.81 
0.63 


1.90 


2.88 


2.93 


5.25 

5.47 


2.42 


2.98 


K63 




3.05 















134 GKOXJND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



Table 33. — Annual range of fluctuation, in feet, of water level in record wells in San 
Diego County, 1912-13 to 1914-15— Continued. 



San Pasqual Valley (deep valley fill). 



Well No. 


Lowering 
of 1912. 


Rise of 
1912-13. 


Lowering 
of 1913. 


Rise of 
1913-14. 


Lowering 
of 1914. 


Rise of 
1914-15. 


Average 
lowering. 


Average 
rise. 


115 




3.04 
1.85 
1.75 


3.71 
2.38 
2.38 


3.93 
2.54 
2.79 


3.52 
1.99 
2.39 


4.08 
2.10 
3.04 


3.61 
2.19 
2.39 


3.68 


H 31 . . . 




2 16 


H 1 




2.52 












2.21 


2.83 


3.09 


2.63 


3.07 


2.79 


2 72 









San Dieguito Valley (deep valley fill). 



G 37. 



10. 80 8. 10 



San Luis Rey River Valley (deep valley fill). 



C 10... 
C 9.... 
B 11.. 
F 21a. 
F 20a. 
F 19.. 
F 17.. 
F 16.. 
F 3... 
F 13.. 
F 11.. 



Average. 



1.29 
3.30 
5.37 
6.94 
5.30 
3.23 
1.68 
3.91 
2.07 
3.18 



3.00 



0.55 
2.51 
4.95 
7.00 
6.61 
2.58 
0.92 
1.37 
1.37 
1.79 



2.00 



0.77 
2.85 
5.28 
7.54 
7.07 
3.43 
1.44 
2.24 
1.56 
1.96 



2.44 



1.68 
2.82 
5.47 
7.46 
7.76 
3.98 
3.06 
4.60 
3.02 
3.65 
2.26 



3.39 



1.69 
2.32 
4.64 
6.55 
6.95 
3.03 
2.33 
3.06 
2.94 
3.70 
2.01 



2.87 



2.33 
3.32 
5.96 
6.95 
5.73 
3.83 
3.49 
4.86 
3.64 
4.95 



4.04 



1.25 
2.82 
5.10 
7.01 
6.44 
3.23 
1.82 
3.07 
2.19 
2.61 
2.01 



1.52 
2.89 
5.46 
7.14 
6.70 
3.46 
2.49 
3.61 
2.68 
3.46 
2.26 



3.09 



a Affected by Libby ditch, not used in averages. 
Fill of minor valleys. 


B 10 


4. 42 3. 58 


3.84 
2.47 


4.18 
6.64 


4.00 
5.43 


3.83 
7.16 


4.09 
3.95 


3.86 


L 91 




0.93 


4.91 








Decomposed granite. 


L 92 




1.41 


2.40 
3.05 
4.78 


1.91 
1.58 
7.97 


2.21 

0.94 
8.86 


4.15 
1.60 
9.80 


2.31 
2.00 
6.82 


2.49 


L 11 




3.12 


H 32 




6.15 


7.97 









The diagrams illustrating fluctuations of the water table (Pis. 
XXXVI to XLII and fig. 18) show four types of annual fluctuation 
that can be associated with (1) the location of the observation wells, 
(2) the depth to ground water just prior to the first heavy storm 
producing run-off, or (3) the permanence of flow of the stream 
traversing the valley in which the well is located. These types are 
described as follows : 

1. Annual fluctuations of wide range, varying from about 4 to 9 
feet and averaging about 7 feet, the fall of the water table continuing 
until the first heavy storm accompanied by run-off. Observation 
wells exhibiting this wide range are those in the upper parts of valleys 
traversed by streams that normally do not flow throughout the year. 
Examples are wells numbered F 4, B 11, L 75, L 63, K 31, L 104, 
O 80, and O 61. 



XT. S. GEOLOC 



IS 



Oct 



LaNa 
Dug 



LaNa 
Duk 



La Mai 



LaNac 
Dug 



La Mac 
Slot 



la/Vac 
Drilled 



Oct. 



M 
IB 



DU 



P. S. GEOLOBICAL SURVEY 



WATER-SUPPLY PAPER 446 PLATE XXXVII 




DIAGRAMS SHOWING FLUCTUATION OF WATER TABLE IN OBSERVATION WELLS IN SWEETWATER VALLEY.! 



U. S. GEOLOGICAL SURVEY 



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DIAGRAMS SHOWING FLUCTUATIO 
JAMACHO 



WATER-SUPPLY 





1914 


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WATER IN THE MAJOR VALLEYS. 135 

2. Annual fluctuations of approximately the average range for the 
major valleys — about 3.6 feet, the water table remaining practically 
stationary from October 1 to the first big storm producing run-off. 
Observation wells showing the average range are in the middle of 
valleys traversed by streams that normally do not flow throughout 
the year. Examples are wells numbered F 17, F 16, F 3, H 5, L 67, 
L 66", L 65, L 42, P 22, O 76, O 20, and O 55. Exceptions to this rule 
are found in parts of Tia Juana and Mission valleys, where heavy 
pumping depresses the water table locally in the middle part of the 
valley. The annual fluctuation in the middle part of Tia Juana 
Valley was 7 to 12 feet and in Mission Valley 5 to 6 feet. 

3. Annual fluctuations of small range, varying in the wells observed 
from 1.1 to 2.3 feet and averaging 1.8 feet, the annual rise of the water 
table beginning about October 1. Such wells are in the lower parts 
of valleys traversed by streams that normally do not flow throughout 
the year. Examples are wells numbered C 6, F 10, H 31, L 72, 
K61, 021, and P 26a. 

4. Annual fluctuations of small range, averaging about 1.5 feet, 
the annual rise of the water table beginning sometime during Sep- 
tember. Such wells are found in all parts of valleys traversed by 
streams that flow continuously throughout the year. Examples are 
wells numbered C 2 and C 10 in San Luis Rey Valley near Pala. 

The explanation of the fluctuations described in paragraphs 1, 2, 
and 3 is to be found in the annual filling and draining of a shallow 
layer of the porous fill of valleys traversed by streams that flow 
during a part of the year. The range of fluctuations is relatively 
large in the upper parts of such valleys and small in the lower parts, 
owing to the tendency of the water table to assume a horizontal 
position after the river ceases to flow. The natural movement of 
ground water is from the upper toward the lower end of the valley. 
The limited cross-sectional area of the fill at the lower end prevents 
free escape of ground water at this point, and the continued arrival 
of ground water from the broader parts of the valley above tends to 
replenish local losses, consisting of seepage return to stream channel 
evaporation, or underflow to the next lower valley. The water table 
at the lower end of the valley thus falls but little during the summer, 
even after the river has ceased to flow. At the upper end of the valley, 
however, replenishment practically ceases as soon as the river ceases 
to flow, and all conditions favor local depletion and lowering of the 
ground water. In the middle part of the valley conditions lie be- 
tween the two extremes. The slow rising of the water level in the 
lower part of the valley after October 1 is due to the diminishing 
losses from evaporation and the accumulation of water from the 
upper end of the valley. In the upper end water levels continue to 
fall slowly until the first storm producing flood run-off. In the 



136 GROUND WATERS OF WESTERN SAN DIEGO COTJNTY, CALIF. 

middle part loss and gain balance each other, and the water level 
remains stationary from about October 1 to the first big storm pro- 
ducing flood run-off. Thus the observed fluctuations are the effects 
of gain and loss and the tendency of the water surface to assume a 
horizontal position in each ground-water reservoir. 

In the fourth group the continued flow of the stream replenishes 
the ground-water supply at the head of the basin throughout the 
year and thus counteracts the tendency of the water table to fall. 
The rate of evaporation begins to decrease in September (Tables 25, 
26, and 27, pp. 101, 102), at which time the water table begins to 
rise through replenishment by lateral percolation from the near-by 
stream. 



Table 34.- 



-Duration of flow of principal streams in San Diego County at typical gaging 
stations. 



San Luis Rey River near Pala. 



Year (July 1 to June 30). 


Date that 
continuous 
flow com- 
menced. 


Date that 
flood flow 

com- 
menced, a 


Date of 

last flood 

flow.a 


Date that 

continuous 

flow 

ceased. 


Number 
of days 
of con- 
tinuous 
flow. 


Number 
of days 
of flood 
flow.a 


Minimum 
flow of 
stream 
during 

nonflood 
period. 


1903-4 


July 1 
...do 


Mar. 23 
Jan. 9 
Jan. 19 
Nov. 23 
Oct. 16 
Jan. 13 
Nov. 11 
Jan. 10 
Dec. 29 
Jan. 15 
Jan. 16 
Jan. 22 

Jan. 2 


May 25 
(June 12) 
June 30 
June 26 
Apr. 26 
May 28 
May 4 
May 2 
May 20 
Apr. 19 
May 16 
June 30 

May 25 


June 30 

...do 

...do 

...do 

...do 

...do 

...do 

...do 

...do 

...do 

...do 

...do 


365 
365 
365 
365 
365 
365 
365 
365 
365 
365 
365 
365 


61 
054) 
143 
209 
144 
135 
159 
106 
74 
37 
118 
160 


Sec. ft. 
1.0 


1904-5 


2.0 


1905-6 


..do. .. 


2.5 


1906-7 


...do.... 


3.0 


1907-8 


...do 


0.6 


1908-9 


. do.... 


2.0 


1909-10 


...do 


5.0 


1910-11 


...do 


(4.0) 


1911-12 


...do 

...do 


1912-13 


3.0 


1913-14 


...do.... 


2.0 


1914-15 


...do 


1.0 








Observed average . 


365 
365 


125 
100 




Corrected aver- 
age *> 





















San Luis Rey River at Bon sail. 



1911-12 




(Mar. 6) 
Jan. 10 
Jan . 1 8 


May 16 
Mar. 30 
May 8 
June 30 


June 17 
June 14 
June 25 
June 30 




(67) 
51 
107 





1912-13 


Dec. 12 
Dec. 1 


177 

207 





1913-14 





1914-15 


Nov. 15 Tan. 9.9 


227 16A 

















Observed average . 




96 
96 




Corrected aver- 



























a Flood flow considered as flow in excess of 14 second feet. 

b Observed average- multiplied by ratio of observed 17-year average on San Diego River at diverting 
dam to observed average for period 1903-4 to 1914-15. 



Water in me major valleys. 



137 



Table 34. — Duration of flow of principal streams in San Diego County at typical 
gaging stations — Continued. 



Santa Ysabel Creek near Escondido and Ramona. 



Year (July 1 to June 30). 


Date that 
continuous 
flow com- 
menced. 


Date that 
flood flow 

com- 
menced, a 


Date of 
last flood 

flow.a 


Date that 

continuous 

flow 

ceased. 


Number 
of days 

of con- 
tinuous 

flow.& 


Number 
of days 
of flood 
flow.a 


Minimum 
flow of 
stream 
during 
nonflood 
period 
(second- 
feet). 


1905-6 


July 1 
...do 


Jan. 19 

Dec. 7 

...do 


June 30 
...do 


June 30 
...do 


365 

365 
365 
269 
358 
180 
264 
304 
278 
278 


150 
212 
150 
170 
163 
135 
85 
63 
129 
157 


0.5 


1906-7 


3.0 


1907-8 


...do 


May 17 
(June 30) 
May 11 
June 4 
May 29 
Apr. 21 
June 9 
June 30 

June 6 


...do 

...do 

...do 

...do 

...do 

...do 

...do 

...do 


1.0 


1908-9 


Oct. 12 
Sept. 23 
(Jan. 9) 
Oct. 15 
Oct. 3 
Nov. 5 
Oct. 11 


Jan. 10 
Nov. 11 
Jan. 9 
Mar. 2 
Jan. 16 
Jan. 19 
Jan. 22 

Jan. 6 





1909-10 





1910-11 





1911-12 





1912-13 





1913-14 





1914-15 











303 


141 
103 



























San Dieguito River at Bernardo. 



1911-12 




(Mar. 7) 
Feb. 23 
Jan. 26 
Jan. 29 


May 22 
Apr. 5 
May 17 
June 23 


June 30 

May 31 
June 28 
June 30 




(72) 
28 
73 

146 





1912-13 


Feb. 1 
Dec. 20 
Jan. 22 


120 
190 
159 





1913-14 





1914-15 













80 
80 




Corrected average. 






























a Flood flow considered as flow in excess of 12 second-feet. 

b Includes number of days flow after July 1, prior to drying up of stream during late summer. 



San Diego River at diverting dam (excluding draft from Cuyamaca reservoir). 



Year (July 1 to June 30). 


Date that 
continuous 
flow com- 
menced. 


Date that 
flood flow 

com- 
menced.o 


Date of 

last flood 

flow.a 


Date that 

continuous 

flow 

ceased. 


Number 
of days 
of con- 
tinuous 
£Low.& c 


Number 
of days 
of flood 
flow.a% 


Minimum 
flow of 
stream 
during 
nonflood 
period 
(second- 
feet). 


1898-99 


(Feb. 1) 
Jan. 2 
Nov. 21 
Jan. 23 
Jan. 26 
Mar. 10 
Jan. 9 
Nov. 5 
July 1 

...do 

Dec. 1 
Nov. 13 
Jan. 8 
Dec. 30 
Jan. 9 
Dec. 20 
Dec. 12 


Mar. 17 
May 5 
Feb. 2 
Feb. 24 
Jan. 30 
Mar. 22 
Feb. 1 
Nov. 5 
July 5 
Oct. 3 
Dec. 1 
Nov. 13 
Jan. 8 
M&r. 5 
Jan. 16 
Dec. 22 
Jan. 29 

Jan. 20 


Mar. 30 
May 6 
May 1 
Apr. 23 
May 22 
Mar. 30 
June 10 
June 30 
June 27 
May 16 
May 31 
May 5 
May 1 
June 2 
Apr. 22 
June 12 
June 20 

May 17 


(May 12) 
(May 31) 
(June 18) 
(June 7) 
(June 16) 
Apr. 9 
June 30 

...do 

...do 

...do 

...do 

...do 

June 6 
(June 30) 
(June 5) 
June 19 
June 30 


101 
149 
209 
135 
141 
30 
172 
237 
365 
365 
257 
229 
149 
182 
147 
191 
200 


8 

2 

41 

40 

97 

5 

121 

170 

201 

166 

150 

141 

97 

80 

54 

106 

143 





1899-1900 





1900-1901 





1901-2 





1902-3 





1903-4 


o 


1904-5 


o 


1905-6 





1906-7 


(2) 
(2) 

o 


1907-8 

1908-9 


1909-10 


o 


1910-11 


o 


1911-12 


o 


1912-13 


o 


1913-14 


o 


1914-15 


o 








192 


96 
96 



























a Flood flow considered as flow in excess of 12 second-feet at diverting dam. 

b Includes number of days flow after July 1, prior to drying up of stream during late summer. 

c Includes period of Cuyamaca Water Co. flume diversion, excepting Cuyamaca draft. 



138 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



Table 34. — Duration of flow of principal streams in San Diego County at typica 
gaging stations — Continued. 

San Diego River at Mission dam. 



at 



Year (July 1 to June 30). 


Date that 
continuous 
flow com- 
menced. 


Date that 
flood flow 

com- 
menced.a 


Date of 

last flood 

flow.a 


Date that 

continuous 

flow 

ceased. 


Number 
of days 
of con- 
tinuous 
flow.b 


Number 
of days 
of flood 
flow .a 


Minimum 
flow of 
stream 
during 
nonflood 
period 
(second- 
• feet). 


1911-12 




Mar. 10 
Jan. 30 
Jan. 26 
Jan. 22 


May 27 
Apr. 7 
Apr. 1 
June 22 


June 20 
June 30 
May 30 
June 30 




(73) 
27 
31 

135 





1912-13 


Dec. 19 
Jan. 1 
Jan. 22 


193 
150 

159 





1913-14 





1914-15 













66 
66 

































a Flood flow considered as flow in excess of 10 second-feet at Mission dam. 

b Includes number of days flow after July 1, prior to drying up of streams during late summer. ' 

Sweetwater River near Descanso. 

















Minimum 




Date that 


Dato that 


Date of 

last flood 

flow.a 


Date that 


Number 
of days 
of con- 
tinuous 
flow. 


Number 


flow of 
stream 


Year (July 1 to June 30). 


continuous 
flow com- 


flood flow 
com- 


continuous 
flow 


of days 
of flood 


during 
nonflood 




menced. 


menced. a 


ceased. 


flow .a 


period 














(second- 
















feet). 


1905-6 


July 1 






June 30 


365 


128 


0.4 


1906-7 


...do 


Dec. 12 


June 15 


...do 


365 


172 


1.1 


1907-8 


...do 


Jan. 25 


Apr. 24 


...do 


365 


34 


0.8 


1908-9 


...do 


Jan. 14 


May 28 


...do 


365 


117 


0.3 


1909-10 


...do 


Nov. 15 


Apr. 15 


...do 


365 


96 


0.8 


1910-11 


...do 


Jan. 10 


Apr. 17 


...do 


362 


58 


0.0 


1911-12 


...do 


Mar 2 


May 12 
Mar. 28 


do 


365 


54 


0.4 


1912-13 


...do 


Jan. 15 


...do 


365 


28 


0.4 


1913-14 


Aug. 16 


Jan. 26 


Apr. 22 


...do 


319 


22 


0.0 


1914-15 


July 1 


Jan. 29 
Jan. 13 


June 23 
May 11 


...do 


365 


146 


0.05 






Observed average. 


360 


86 
















63 



















a Flood flow considered as flow in excess of 10 second-feet. 

The diagrams (Pis. XXXVI to XLII) also illustrate differences in 
conditions with respect to the rise of the water table, as follows : 

1. In wells somewhat remote from stream channels and in places 
not subject to floods maximum ground-water level is attained within 
about seven days of the first heavy storm producing flood run-off 
and with no relation to the distance of the well from the river chan- 
nel. At the observed wells of this class the depth to water just 
previous to the storm was 6.6 feet or less (Table 35). Such wells 
are numbers H 31, O 76, F 13, F 16, L 86, H 5, K 82, and C 10. 

2. In wells somewhat remote from stream channels and in places 
not subject to flooding maximum ground-water level each year is 
attained gradually after the first heavy storm producing flood run. 
off, the time varying in the wells observed from 15 to 161 days and 
averaging 52 days, and depending somewhat on the distance of the 












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66 
























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WELL L 63 




/ 






















10 ft deep, elevation 


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At. I! \N 



i\\ 



FLUCTUATIONS OF WATER TABLE 
IN OBSERVATION WELLS 

IN UPPER SAN DIEGO WIVE IS VALLEY 

1912 - 1915 

NOTE: Dotted II 



WATER IK THE MAJOR VALLEYS. 139 

well from the river channel. At such wells the depth to water just 
before the storm is more than 6.6 feet (Table 35). Such wells are 
those numbered O 61, O 55, K 31, L 67, K 62, K 83,*F 20, K 61, F 21, 
L 66, L5,L 7-a, O 118, B 11, O 80, and L 75. 

3. In wells near a stream or in places subject to flooding maximum 
ground-water level is reached either during the period of greatest 
flood flow of the season or immediately thereafter. Such wells are 
numbers C 7, F 19, H 36, H 34, L 71, L 7-d, L 70, L 76, K 118, K 107, 
K 85, K 63, P 23, O 78, O 127, O 130, and O 123. 

The conditions represented by the first and second groups are 
explained as follows : The precipitation from a storm that produces the 
first flood run-off usually amounts to 2 to 4 inches on the valley floor 
and has generally been preceded by several inches of rain during 
the current rainy season. If a porous material contains capillary 
moisture from the zone of saturation up to the surface of the ground, 
water applied to the surface passes down rapidly to the zone of 
saturation. If, however, the surface layers of the material are dry 
to an appreciable depth below the surface, the water that is absorbed 
must cover the dry soil grains with a film of moisture and fatten the 
depleted water films of the soil grains below the surface before it 
will pass down to the zone of saturation. The vertical distance 
through which the materials composing the fill of the valleys in San 
Diego County will draw capillary moisture from the zone of satura- 
tion ranges from 2.5 feet in the coarsest sands to 7 or 8 feet in the 
fine silts; For average porous materials, in which the zone of satu- 
ration is less than 7 feet below the surface and the moisture films in 
the upper layers have already been somewhat replenished by recent 
storms, the conditions are ideal for rapid absorption and trans- 
mission to the zone of saturation of the water of the first big storm 
that produces flood run-off. This is the condition at the first group 
of wells (Table 35). The immediate rise of the water table to maxi- 
mum, as observed in most of these wells is due to replenishment 
from direct rainfall during the storm that produces the first flood 
run-off and not to transmitted pressure or absorption from run-off. 
This conclusion is confirmed by study of the second group of wells, in 
which the depth to water exceeded 7 feet. 



140 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Table 35. — Time required for water table to reach maximum levels after first storm that 

produces run-off. 



Well No. 


Major valley. 


Depth to 
water 

table just 

prior to 
first 
storm 

that pro- 
duced 
flood 

run-off. 


Distance 

of well 

from river 

channel. 


Date of 

beginning of 

first storm 

that produces 

flood run-off. 


Date of 
arrvial of 
first flood. 


Approxi- 
mate date 
of highest 
level of 
water 
table. 


Period 

be- 
tween 

first 

flood 

and 
highest 
water 
level. 


H31 


San Pasqual 


Feet. 

1.2 

2.7 

4.0 

4.7 

4.8 

6.1 

6.6 

6.6 

7.4 

8.2 

9.2 

9.2 

9.3 

9.4 

9.6 

9.8 

10.5 

10.6 

11.0 

11.7 

13.0 

13.3 

13.9 

19.4 


Feet. 

520 

150 

2,100 

2,200 

1,500 

2,200 

1,700 

520 

900 

2,150 

300 

500 

150 

1,000 

1,500 

1,000 

1,300 

1,350 

1,000 

820 

2,340 

500 

260 

1,040 


Jan. 27,1915 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 


Jan. 29,1915 

do 

do 

do 

do 

do 

do 

.....do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 

do 


Feb. 1 

...do 

Feb. 5 

...do 

Feb. 3 
Feb. 1 
Feb. 4 
Feb. 5 
May 1 
June 29 
Feb. 18 
Mar. 11 
Feb. 12 
Feb. 18 
Mar. 12 
Mar. 31 
Feb. 24 
Mar. 11 

...do 

Feb. 13 
Mar. 30 
Feb. 24 
Feb. 27 
Mar. 18 


Days. 
2 


76 


2 


F 13 


San LuisRey 

do 

Upper San Diego. . 

San Pasqual 

Mission 


7 


F16 

L86 


7 
5 


H5 


2 


K82 


6 


C 10 


San LuisRey 

Tia Juana. 


7 


61.. 


92 


055 

K 31 


.....do 


161 
20 


L 67 


Upper San Diego. . 
Mission 


41 


KG2 


14 


K83 

F20 


do 

San Luis Rey 


20 

42 


K61.... 


61 


F21. . 


San LuisRey 

Upper San Diego.. 

do 

do 

Tia Juana 


26 


L66 


41 


L5 

L7-a 

OH8 


41 
15 
60 


B 11... 


San Luis Rey 

Sweetwater 

Upper San Diego.. 


26 


80... 


29 


L75 


48 







Note.— Wells not surrounded by or near to standing or flowing surface water were protected from inflow 
of surface water by curbing or otherwise. 

At no wells of this group, whether relatively near or at a consider- 
able distance from the river, was the maximum water level attained 
within a period less than 14 days, the average being 52 days, whereas 
the longest period among the wells of the first group was 7 days. 
The time elapsing does not necessarily vary proportionally to the 
distance of the well from the river, because in some places the maxi- 
mum level occurs with the arrival of the crest of the ground-water 
wave traveling outward from the river, whereas in others it occurs 
with the arrival of the absorbed rainfall from above. The facts are 
brought out by Table 35, on which the wells are arranged in order 
of their depth to the water table just prior to the first storm producing 
flood run-off. The conclusion is that the attainment of maximum 
ground-water level at the time of the first storm producing flood 
run-off in wells not influenced directly by the river or overflow 
water is due to the absorption and immediate transmission of rain- 
fall directly to the zone of saturation, made possible by an initial 
moist condition of material from the zone of saturation to the surface 
of the ground. 

In the third group the quick rise of the water table to maximum 
level in wells near a stream or on ground that is subject to flooding 



WATER IN THE MAJOR VALLEYS. 141 

is obviously due to direct contact of surface water with the adj acent 
porous formation. 

In some ground-water reservoirs the water table undergoes broad 
periodic fluctuations, the periods covering several years, upon which 
the annual fluctuations are superimposed. Examination of the 
diagrams showing fluctuations of the water table in the observa- 
tion wells since 1912 (Pis. XXXIX to XLII) and consideration 
of other more general information indicate that in the ground- 
water reservoirs of San Diego County, however, the broader periodic 
fluctuations are unimportant as compared with the annual fluctua- 
tions. The maximum level attained in dry years, as shown by the 
diagrams, is in most wells less than a foot lower than the maximum 
level in wet years, and the minimum level of dry years is always less 
than a foot lower than the minimum level of wet years. This varia- 
tion in the maximum and minimum levels of wet and dry years 
is but a fraction of the total annual fluctuation. The only water- 
level observation available for the protracted period of drought from 
1897-98 to 1903-4 is a measurement at well numbered L 83, in the 
upper San Diego River valley at Riverview, reported by Mr. C. S. 
Alverson. This measurement was made November 22, 1904, at 
practically the end of the dry period, and indicated a level several 
feet higher than the minimum of 1914 (PL XL). The ground- 
water levels in the vicinity of well L 83 have been affected since 1911 
by pumping at well L 82, which is about 750 feet upstream. This 
measurement indicates that with natural conditions a protracted 
drought results in only a minor depression of the water table, a 
conclusion that is also confirmed by the statements of cattlemen 
who during this same dry period found it possible to obtain water 
for stock at many points in the river beds by merely scooping out 
basins 2 to 4 feet in depth. The only unusual depressions of the 
water table reported in this period were in the immediate vicinity 
of pumping plants making heavy drafts. 

The explanation for this stability of the water table in periods of 
severe drought is to be found in the very slight opportunity for escape 
of ground water when its surface has fallen below the comparatively 
shallow depth within which moisture is lost by evaporation. The 
slope downstream is so gradual and the material through which the 
water must move is so fine that the velocity of underflow is very small 
and permits but slight depletion of the ground-water reservoirs after 
the normal low-water stage of November 1 has been reached. This 
condition serves greatly to enhance the value of the ground-water 
reservoirs as sources of reserve supply in dry years. 



142 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

GROUND- WATER YIELD. 
ECONOMIC REQUIREMENTS. 

The quantity of water that can be drawn from a ground-water 
reservoir — the ground-water yield — may be considered either as the 
net quantity that can be withdrawn during average or wet years and 
completely restored to the reservoir in immediately following average 
or wet years, or as the net quantity that can be withdrawn during every 
year, including years of extreme and protracted drought, and com- 
pletely restored within a period of one or two years. 

The first quantity, which may be termed the average yield, can be 
considered as the quantity available to the irrigator as distinguished 
from the user of water for domestic supply, whose needs limit him to 
the second quantity, termed the safe yield. 

Two classes of irrigation enterprises in San Diego County may 
depend on underground reservoirs for water — one designed for the 
cultivation of field crops of moderate value, such as vegetables, sugar 
beets, or alfalfa, chiefly in the valley land overlying or bordering the 
underground reservoirs, the other designed for the cultivation of 
orchards, chiefly on mesa and foothill lands. The permanent 
investment, other than that for land, buildings, and equipment, 
represented by enterprises of the first class, is small, and the inability 
to obtain an adequate water supply during any season involves little 
loss except the crop for that year. This loss can be better afforded 
than the loss which would result from permitting the land to lie 
fallow, as exceptional droughts ordinarily occur only once in 7 to 10 
years. The orchards irrigated consist almost entirely of citrus fruit 
trees, which represent a large investment and produce a valuable 
crop. A full supply of water is required to produce an income- 
yielding crop from fruit trees, although the trees can be kept alive 
and the investment saved from destruction with only one-half a full 
supply. Furthermore, the seepage water from orchard lands is 
usually considerably less than that from lands devoted to field crops, 
and unlike the water applied to field crops seldom finds its way 
directly back to the valley from which it was drawn. Thus the 
amount of water developed from an underground reservoir for the 
supply of orchard trees must be less than for field crops. Consider- 
ing irrigation in general, however, it is not absolutely necessary that 
a full supply be obtainable in dry years, and with proper modifica- 
tions the average yield may be considered a safe basis for planning 
irrigation systems. 

For domestic and general municipal uses, however, a full supply of 
water must be available every year and at all times of the year to 
assure protection from fire and to avoid the dangers of water famine. 
To meet these requirements and to insure an absolutely reliable supply 



WATER IN THE MAJOR VALLEYS. 143 

through the most severe droughts sufficient available ground water 
must be in storage in the valley fill to supply the draft during a 
period of at least three years in which the reservoir receives practically 
no replenishment from rainfall and run-off, such periods of drought 
as are indicated by Tables 18 and 20, pages 84 and 95. 

The cost of pumping is not so vital a limitation on the safe yield as 
on the average yield. The greatest depth from which the water can 
be economically pumped for irrigation depends on the amount the 
irrigator can afford to pay for pumped water. Generally speaking, 
this depth is less than that of the water-bearing formations of the 
major valleys. The greatest depth from which water can be econo- 
mically raised for domestic supplies is determined largely by the 
depth of the water-bearing formations and the percentage of the 
voids or spaces in them that can be drained at different levels. The 
water-bearing formations of the major valleys of San Diego County 
lie at comparatively shallow depths, and the operation of the pump- 
ing plants should present no insuperable difficulty even if the draw- 
down in wells should reach to the bottom of the valley fill. 

AVERAGE YIELD. 

Replenishment of reservoirs. — The average yield of the ground- 
water reservoirs of San Diego County — the net quantity that can be 
withdrawn during an average or wet year and completely restored 
during a following average or wet year — is about equal to the aver- 
age natural replenishment of the ground water, which can be more 
or less definitely computed for each major valley. The accurate 
computation of the annual replenishment requires a clear knowledge 
not only of the various sources of ground-water supply and of ground- 
water losses, but a knowledge of the time of supply and loss in the 
annual cycle and of their quantities and proportions. 

The ground-water reservoirs under consideration are replenished 
by absorption (1) from rain that falls on the valley fill, (2) from 
streams that flow through the valleys, and (3) from the run-off 
from adjacent hill slopes. Water absorbed from precipitation perco- 
lates downward to the zone of saturation and gradually raises all parts 
of the water table. Water absorbed from a stream flowing through 
the valley builds up a ground-water ridge that widens in each direc- 
tion from the channel and raises the water table as it moves. 

The heaviest rains in the major valleys occur during December to 
March (fig. 5). The most effective replenishment of ground-water 
storage, however, is during January to March (Pis. XXXVI to 
XXXIX, XLII, and Table 35). The proportion of the ground-water 
replenishment derived directly from rainfall under average condi- 
tions is estimated at 35 per cent, although it varies widely, depending 
on the amount of the annual rainfall and the intensity and time of 
occurrence of individual storms. 



144 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Absorption from stream flow is most rapid during the early part 
of the flood-flow period (Pis. XXXVI to XLII, and PI. XIX) but 
continues until the flow entirely ceases. The flood-flow period nor- 
mally begins in January and lasts about 100 days. The following 
table (table 36) summarizes the data regarding the flood-flow period 
on different streams as given in greater detail in Table 34, page 136. 

Table 36. — Summary of data showing duration of flood flow, in days, for principal 
rivers in San Diego County. 



Season. 


San Luis 
Rey River 
near Pala. 


San Luis 
Rey River 
at Bonsall. 


Santa 

Ysabel 

Creek near 

Ramona. 


San 
Dieguito 
River at 
Bernardo. 


San Diego 

River at 

diverting 

dam. 


San Diego 

River at 

Mission 

dam. 


Sweetwater 
River at 
Descanso. 


1898-99 










8 

2 

41 

40 

97 

5 

. 121 

170 

201 

166 

150 

141 

97 

80 

54 

106 

143 






1899-1900 














1900-01 














1901-02. .. 














1902-03. .. 














1903-04 


61 
154 
143 
209 
144 
135 
159 
106 
74 
37 
118 
160 












1904-05 .. 












1905-06 . . 




150 
212 
150 
170 
163 
135 
85 
63 
129 
157 






128 


1906-07. .. 








172 


1907-08 








34 


1908-09 








117 


1909-10 . . 








96 


1910-11. . 








58 


1911-12 


(67) 
51 
107 
160 


(72) 
28 
7) 

146 


(73) 
27 
31 

135 


54 


1912-13 

1913-14 


28 
22 


1914-15 


146 






Observed average. 
Corrected a verage. 


125 
103 


96 
96 


141 
103 


80 
80 


96 
96 


66 
66 


86 
63 


Average date of 


Jan. 2. . 




Jan. 6. .. 




Jan. 20... 




Jan. 13. 


Flood flow con- 
sidered as any 
flow in excess of. 


14 sec.-ft. . 


14 sec.-ft. . 


12 sec.-ft. . 


12 sec.-ft. . 


12 sec.-ft. . 


12 sec.-ft. . 


10 sec.-ft. 



The flow of San Luis Key River at the head of its major valley is con- 
tinuous throughout the year but reaches a minimum ranging in different 
years from 1 to 5 second-feet. The flow of other streams is continuous 
in some years, but usually ceases during the summer and fall (Table 34) . 
Flow other than flood flow is completely absorbed by the valley fill 
before it reaches the ocean. It is interesting to observe the advance 
of the end of San Luis Rey River after September 15. During the 
summer the end of visible flow is usually just above the well num- 
bered C 9 on Plate XXV; in September it begins to advance down- 
stream at a rate of about 170 feet a day, the water filling the depleted 
sands beneath and adjacent to the channel, and thus building up a 
broad ground-water ridge. In the canyon below Bonsall the advance 
is more rapid, for the depth to the water table is small. The rate of 
advance in 1914, as observed by the writer, was 1,360 feet a day. If 
not previously overtaken by flood flow the end of this stream advances 
to the head of Mission Valley by the middle of January. 

The rate at which the ground absorbs water from stream flow at 
any time depends, among other things, on the relative elevations of the 
water surface in the channel and in the subjacent valley fill and on the 



WATEK IN THE MAJOR VALLEYS. 



145 



area of channel in contact with the flowing stream. The total volume 
annually absorbed from run-off depends, in addition, on the length 
of the period of flow, which in the major valleys usually far exceeds 
the period required to bring the water table to its maximum elevation. 
The average date of latest flood flow is sometime late in May or 
early in June (Table 34, p. 136), whereas the date of maximum ground- 
water level is late in March or early in April (Tables 32 and 33, 
p. 133). When evaporation becomes more effective than recharge 
the water table begins to go down. The quantity of water normally 
absorbed from flood run-off is only a small proportion of the total 
run-off, and large quantities of water annually flow unused into the 
ocean. 

Table 37. — Comparative discharge measurements of principal streams of San 

County in 1914-15. 

Tia Juana River. 



Point of measurement. 


Distance 
between 
points of 
measure- 
ment 
(miles). 


Date. 


Measured 
flow of 
river 
(second- 
feet). 


Total gain 
(+)orloss 
(-)in 
second- 
feet. 


Gain(+) 
or loss (— ) 
in second- 
feet per 
mile. 


2£ miles above international boundary . . 


| 2.5 
} 2.8 

} " 


{jan. 19, 1915 

/....do 

\....do 

/....do 

\....do 


{ 0.86 







} - 0.85 

} ° 
} ° 




I)o 




Nestor bridge 





Do 




Near Pacific Ocean 











} 2.8 
} ,5 


/Apr. 6,1915 

\ do 

/....do 

\....do 


44.0 
47.0 
47.0 
37.0 


} + 3.0 
} -10.0 






+1.1 


Do 




Near Pacific Ocean 


—6.7 






Total 


4.3 




- 7.0 


— 1.63 










International boundary 


} 2.8 

} , 5 


/Apr. 10,1915 

1 do 

/....do 

\....do 


33.0 
32.0 
32.0 
26.0 


} - 4.0 
} - 6.0 




Nestor bridge 


—1.4 


Do 






-4.0 






■ Total 


4.3 




-10.0 


—2.33 











Sweetwater River. 



Jamacho bridge. 



7 k /Apr. 5,1915 
7 ' 5 i....do 



26.2 
24.0 



2.2 



-0.29 







San Diego River. 








El Capitan 


} 


5.8 


/Mar. 31,1915 
\....do 


51.0 
45.0 


} - 6.0 




Lakeside 


—1.03 






Do 


} 
} 


8.0 
11.5 


/Apr. 3,1915 

\ do 

/....do 

\Apr. 4, 1915 


37 
a 51 
a 51 
6 56. 


} + i.o 

} ° 




Old Mission dam 


+0.13 


Do 




Old Town 









Total 


19.5 




+ 1.0 


+0.05 


Old Mission dam 


} 


9.0 


/June 2, 1915 
\....do 


72.2 
c64.8 


P^ - 




Near San Diego 









a Includes inflow into river from San Vicente Creek (Mar. 3, 1915) of 13.0 second-feet. 

b Includes net effect of inflow into river from Alvarado Canyon (Mar. 4, 1915) of 12.0 second-feet, and loss 
by diversion at city pumping plant (Mar. 4, 1915) of 7.0 second-feet. 

c Includes net effect of inflow into river from Alvarado Canyon (June 2, 1915) of 3.0 second-feet 
estimated), and loss by diversion at city pumping plant (June 2, 1915) of 8.3 second-feet. 



115536°— 19— wsp 446- 



-10 



146 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



Table 37 — Comparative discharge measurements of principal streams of San Diego 
County in 1914-15 — Continued. 



San Vicente Creek. 



Point of measurement. 


Distance 
between 
points of 
measure- 
ment 
(miles). 


Date. 


Measured 
flow of 
river 

(second- 
feet). 


Total gain 
(+) or loss 
(-)in 
second- 
feet. 


Gain(+) 
or loss (— ) 
in second- 
feet per 
mile. 


Foster 


} 3.3 


/Apr. 5, 1915 
\ do 


10.0 
10.0 


} ° 




Near Lakeside 










3an Luis Rey River. 












} 


12.0 


/Feb. 5,1915 
\....do 


268 
325 


} 


+57 






+4.8 






Pala (800 feet east of bridge) 


} 

> 


8.0 
9.0 


/Mar. 17,1915 

\....do 

/....do 

\Mar. 18,1915 


71 
73 
73 

67 


} 
} 


+ 2 
- 6 






+0.25 


Do 






—0.67 






Total 


17.0 




- 4 


—0.23 




I 





Depletion of the reservoirs. — Ground-water reservoirs lose water 
naturally (1) by evaporation of moisture raised by capillarity from the 
zone of saturation to the surface soil, (2) by transpiration from vege- 
tation drawing moisture from the zone of saturation, (3) by return of 
water to the channel of the river or by underflow through the fill in 
the contracted neck at the lower end of the valley, and (4) by leakage 
into surrounding formations. 

Losses due to evaporation occur wherever the zone of saturation is 
sufficiently close to the surface to permit the continued upward 
capillary movement of water to replace that lost by evaporation. The 
capillary limit varies from about 2 J to 8 feet, depending on the type of 
soil and the relative sizes of sand grains. Loss continues so long as 
the zone of saturation is within the capillary limit and is greatest 
between the middle of April and the middle of September. The 
rate of capillary movement of the water varies with the depth to 
the water table, so that the rate of loss is not the same in different 
parts of the areas of discharge nor at the same point at different times 
of the year, because of the lowering of the water table as the season 
advances. In this connection it has been suggested that losses due to 
evaporation might be eliminated by artificially lowering the water 
table below the capillary limit. 

Transpiration in the area underlain by the valley fill occurs prin- 
cipally from native trees, such as willow, sycamore, and alder; from 
natural grasses and close-growing plants, such as saltgrass, yerba 
mansa, and samphire; and from growing crops, such as alfalfa, sugar 
beets, and grain. The moisture may be either absorbed by the roots 
from capillary water drawn directly from the zone of saturation or 
from water applied to the surface in irrigation. The rate of transpira- 



WATER IN THE MAJOR VALLEYS. 



147 



tion in any area depends on the kinds of plants and on the luxuriance 
and density of their growth. The losses are confined to the growing 
season and are most active while the leaves are green. 

The losses from the underground reservoirs by return of water to 
the streams are negligible. During the flood-flow period such losses 
may occur at the borders of the channels where the material becomes 
saturated to the level of the flood crests, the moisture draining out to 
the level of the permanent stream within a few days after the flood 
peak has passed. Comparative discharge measurements made by 
the writer during March to June, 1915, at critical points on Tia Juana, 
Sweetwater, San Diego, and San Luis Key rivers (Table 37) show no 
increase in the flow of the streams as they pass through the different 
valleys and indicate that during the summer and fall the return flow 
is practically zero. The same fact is also shown by the following 
tables (38 and 39) compiled from records of the United States Geo- 
logical Survey of the flow at critical points on San Luis Rey, Santa 
Ysabel, San Dieguito, and San Diego rivers. 

Table 38. — Monthly discharge, in acre-feet, at gaging stations on three rivers in San 
Diego County for the period June to December, 1914, following a rainy season in which 
run-off was less than the average. 



Stream and point of measurement. 



June. 



July. 



August. 



Sep- 
tember. 



Oc- 
tober. 



No- 
vember. 



Decem- 
ber. 



San Luis Rey near Pala. . . 
San Luis Rey at Bonsall... 
San Luis Rey at Oceanside 

Santa Ysabel near Ramona 
San Dieguito at Bernardo . . 
San Dieguito near Del Mar. 

San Diego at Lakeside 

San Diego at Mission dam. 
San Diego at San Diego — 



77 


522 
24 


29 





252 





117 



6 










257 





314 

32 



125 




6 




515 

385 



397 





T.able 39.' — Monthly discharge, in acre-feet, at gaging stations on three rivers of San 
Diego County, for the period June to September, 1915, following a rainy season in which 
run-off exceeded the average. 



Stream and point of measurement. 



June. 


July. 


August. 


4,020 


588 


432 


4,480 


300 


13 


5,370 








2,800 


959 


569 


1,760 


54 


53 


1,620 


66 


1 


698 








74 









Septem- 
ber. 



San Luis Rey near Pala. . : . 
San Luis Rey at Bonsall . . . 
San Luis Rey at Oceanside. 

Santa Ysabel near Ramona 
San Dieguito at Bernardo . . 

San Diego at Lakeside 

San Diego at Mission dam.. 
San Diego at Old Town 



232 




The data obtained at these stations, all of which are at contracted 
places in the valleys, show that during the summer and fall the 
ground-water reservoirs do not, as a rule, lose by surface flow at the 



148 

lower end, even in a wet year, but rather that they absorb all water 
entering them. The increased flow during June, 1915, at lower 
stations on San Luis Rey River is due largely to inflow from lateral 
tributaries but in part to return water caused by the draining out 
of water absorbed by the channel bank during the protracted floods 
of early May. 

Loss by underflow through the fill of the contracted neck at the 
lower end of the valleys is also very small. In San Pasqual, upper 
San Diego, and upper Sweetwater valleys, no such loss can occur, 
because at their lower ends these streams flow through rock-bottomed 
canyons. The fill of upper San Luis Rey Valley is connected with 
that of the lower valley by a neck of sand about 5 miles long, which 
fills an old canyon in the granite. The fill in this canyon is 60 feet 
thick at the deepest point and ranges in width from 400 to 800 feet. 
The slope of the water table is about 1 2 feet to the mile. The average 
velocity of underflow at a selected cross section of this canyon fill near 
Bonsall was determined by the writer from 1 1 separate observations 
made by the Slichter method at points well distributed through the 
section, and was found to have an average value of 5.14 feet a day, or 
about one-third of a mile a year. The rate of underflow in the entire 
section was 0.47 cubic feet a second, or 340 acre-feet a year. The con- 
ditions were probably favorable for a rate of flow greater than the aver- 
age for the year for there was flow on the surface during the period of 
measurement. The loss by underflow from the upper San Luis Rey 
Valley can thus be set down as less than 340 acre-feet per annum. 
This loss, however, is without doubt more than offset by the under- 
flow into the valley at the gaging station near Pala. 

The conditions for underflow from the coastal valleys into the 
ocean are even less favorable than the conditions at the section near 
Bonsall. The sands of the valley fill near the coast are much finer 
than those in the upper valleys, the slope is gentler, and there is 
back pressure from the ocean. All the valleys except Tia Juana 
visibly contract in cross section before reaching the ocean, and if 
well logs were available it might be found that this valley also closes 
up below the surface. Thus the conditions do not indicate appreci- 
able loss by underflow from the coastal valleys. 

Loss from ground-water reservoirs in San Diego County by leakage 
into the surrounding formations is, in general, impossible, for those 
formations are relatively impervious. Moreover, the valleys lie far 
below the adjacent general surface and below the bottoms of tribu- 
tary valleys. The conditions are therefore more favorable for receiv- 
ing water from the adjacent formations than for yielding water to 
them. However, the contours of the water table (PL XX) north of 
the lower half of Tia Juana Valley and on both sides of the lower part 
of Sweetwater Valley, as drawn for January 6 and March 1, 1915, 



WATER IN THE MAJOR VALLEYS. 149 

apparently show some loss of ground water, but the amount is only 
a small percentage of the total replenishment for Tia Juana Valley 
south of Nestor. This is the only valley, however, in which any 
evidences of loss by lateral percolation were observed. 

Summarizing the discussion of ground-water losses, it may be said, 
first, the only large natural ground-water losses from the major 
valleys of San Diego County, except the possible leakage out of Tia 
Juana Valley, are due to evaporation and transpiration; and, second, 
that the ground-water losses during the annual period of the lowering 
of the water table (about Apr. 1 to Nov. 1) are nearly equal to the 
volume of water represented by the lowering of the water table plus 
the volume of water absorbed from streams during the same period. 

Relation of replenishment to loss. — The additions to the ground- 
water supply during any season tend either to raise the water table 
or to retard its lowering. The losses, on the other hand, tend either 
to lower the water table or to retard its rise. The difference in level 
of the water table at any two dates is directly proportional to the 
difference in the accretions and losses during the period between 
these dates. If the accretions are in excess the water levels rise; 
if the losses are in excess the water levels fall; if accretions and losses 
are equal the water levels remain stationary. Table 33, which sum- 
marizes observations on fluctuations of ground water in the major 
valleys since 1912, shows that for a series of three years, including 
one dry, one average, and one wet year, the average annual rise of 
the ground-water is practically equal to the average annual lowering. 
The stability of the water table over long periods is also indicated 
by the statements of local residents. Hence it can be concluded that 
over a series of years the ground-water rise is nearly equal to the 
ground-water lowering and therefore that average annual additions 
to ground-water supply about equal average annual losses. 

Method of computing annual additions to supply of ground water. — 
The conclusions presented in the last two paragraphs can be made 
the basis of a simple method of computing the volume of the average 
annual additions to the ground-water supply of the underground 
reservoirs. For simplicity in analysis the following terms will be 
used: 

A=average volume, in acre-feet, annually absorbed from run-off (both stream flow 
and run-off from adjacent slopes). 

B=average volume, in acre-feet, annually absorbed from direct rainfall on the 
surface of the valley fill. 

C=average volume, in acre-feet, annually lost by evaporation and transpiration. 

D=average volume, in acre-feet, annually lost by leakage into adjacent formations. 

E=average annual fluctuation of water table, in feet, throughout the areas under- 
lain by valley fill. 

K= effective porosity; that is, the ratio of depth of actual water represented by 
fluctuation of water table, if spread over an equal area, to observed fluctuation. 



150 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

S=area underlain by valley fill, in acres. 

a=average volume, in acre-feet, annually absorbed from run-off during period of 

lowering of the water table (Apr. 1 to Nov. 1). 
c=average volume, in acre-feet, annually lost by evaporation and transpiration 

during period of lowering of the water table (Apr. 1 to Nov. 1). 
m=ratio of loss by evaporation and transpiration in the period April 1 to October 

31, to the loss during the whole year. 

The two following relations exist among the above quantities as a 
result of the conclusions stated: 

(1) c=(ExKxS)+a. 

(2) A + B = C + D. 

A third relation exists by reason of the definitions of terms used. 

(3) c = mxC. 

As a result of these relations and by performing simple algebraic 
operations the following relation exists : 

(4) A+B = ^±a +D . 

Values for all elements of the second member of this equation are 
available from observations made during the years 1912 to 1915, 
as follows: 

E, the average annual fluctuation of the water table, is known 
from direct observation for the period 1912-1915 in upper San Diego, 
San Pasqual, and San Luis Rey valleys (Table 33). The average 
rise is determined from observations for the season 1914-15 in all 
majorvalleys (Table 32). The ratio of the average rise for the season 
1914-15 to the average annual fluctuation for the three valleys for 
which complete data are available is 1.30 (Table 33). The average 
annual fluctuation for other valleys can be approximately obtained 
by applying this ratio. 

K, the effective porosity — that is, the percentage by volume of the 
porous valley fill drained and filled by the annual fall and rise of the 
water table — has been estimated from the results of several porosity 
tests, described on pages 121-123, at 34 per cent. This percentage 
undoubtedly varies considerably in different valleys and was deter- 
mined approximately for each valley by a study of local conditions. 

D, the average quantity lost by leakage into adjacent formations, 
is believed to be negligible for all the valleys except Tia Juana Valley, 
for which 500 acre-feet was adopted as more nearly the average than 
the quantity lost in 1915 (pp. 146-149). 

a, the average quantity absorbed during the lowering of the water 
table, was computed from run-off data obtained by the United States 
Geological Survey at gaging stations in each valley during the years 
1912 to 1915, and was averaged for each valley. The results should 
be very close to an average for a long period. (See Table 20.) 

m, the ratio of loss by evaporation and transpiration from April 1 
to October 31 to the loss during the year, was computed from the 



WATER IN THE MAJOR VALLEYS. 



151 



three-year record of evaporation obtained from a floating pan at 
La Mesa reservoir (Table 26, p. 102). The average ratio of the loss 
by evaporation from this reservoir from April 1 to October 31 to the 
loss for the whole year for the three years 1913 to 1915 is 0.752. 

S, the area, in acres, underlain by the valley fill, was computed by 
planimeter from Plates XX to XXV, and included the area of both 
deep and shallow fill in the major valleys. The area of valley fill 
at the head of Tia Juana Valley in Mexico, about 690 acres, is in- 
cluded. 



Table 40. — Observed and computed data regarding ground-water intake in major valleys 
of San Diego County, Calif. 



Valley. 


S. 


E. 


K. 


D. 


a. 


m. 


A+B. 


Santa Margarita 


Acres. 
3,640 
4,376 
3,270 
1,880 
2,210 
3,120 
2,470 
1,065 
1,532 
4,380 


Feet. 
(3.00) 
3.00 
3.00 
3.60 
(3. 00) 
4.28 
4.00 
3.16 
2.08 
5.45 


Per cent. 
(0.33) 
.38 
.32 
.38 
.33 
.38 
.33 
.38 
.33 
.31 


Acre-feet. 









700 


Acre-feet. 
(1,000) 
1,910 

820 
2,220 

360 
1,040 

200 

420 


910 


0.752 
.752 
.752 
.752 
.752 
.752 
.752 
.752 
.752 
.752 


Acre-feet. 
6,115 


San Luis Rey (upper) 


9,180 


San Luis Rey (lower) 


5,270 
6,380 
3,390 
8,130 
4,600 


San Pasqual 


San Dieguito 


San Diego (upper) 


Mission 


Sweetwater (upper) 


2,260 




1,400 


Tia Juana 


11,550 






27,943 




I 






58,275 






1 







Note.— The quantities in the last column of the table (the term A+B of equation 4) represent the average 
annual additions : to ground water from all available sources. The quantities in parentheses are approxi- 
mate. 

Accuracy of computations . — As several of the factors in the computa- 
tions are based on inadequate data the determinations contain a 
large percentage of error. The greatest uncertainty exists in regard 
to the effective porosity (K), on account of the small number of 
porosity tests that were made, in regard to the average annual 
fluctuation of the water table (E), and the volume of stream water 
(a) absorbed from April 1 to November 1 , on account of the shortness 
of the periods of observation. 

The average annual yield — that is, the maximum quantity that 
can be withdrawn for use from year to year without depleting the 
supply — is not the same as the intake, which is shown in the last 
column of Table 40. The yield can be definitely determined only 
by large development and use of the water for a period of years. 
One of the principal elements of uncertainty in the relation of intake 
to yield is the extent to which the installation and use of pumping 
plants will reduce evaporation and transpiration from uncultivated 
land. Pumping at wells whose circle of influence includes the stream 
channel at a period when the stream is still flowing draws some water 
directly from the stream. Table 34 (p. 136) shows that this period 
usually includes the months April, May, and June. By lowering 
the water table below its normal level at the end of the season (Nov. 



i52 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

1), pumping withdraws water that would otherwise remain in the 
ground, and this water is replaced during the succeeding rainy- 
season. These processes represent absorption from run-off in excess 
of the natural absorption. By prematurely lowering the water 
table over more or less extended areas during May to October, 
pumping reduces natural losses from evaporation, for it withdraws 
ground water that would otherwise be lost into the atmosphere. 
This process substitutes evaporation and transpiration from culti- 
vated fields for that from uncultivated land. Where most of the 
large wells are within about 500 feet of the stream channel and the 
normal period of flow of the stream extends well into June, the yield 
may be greater than the natural ground-water recharge; where 
most of the large wells are more than 500 feet from the stream channel 
and the normal period of flow of the stream ends in April or earlier, 
the yield may be less than the natural recharge. If the wells 
draw extensively from a large body of open gravels that lie under 
finer materials, as in Tia Juana Valley, and if the gravels receive 
much water directly from the stream in the upper part of the valley, 
as they may in this valley, the yield may exceed the natural recharge. 
It is not possible with the available data to classify more definitely 
the valleys with respect to relation of yield to normal recharge. 

If the total intake (see last column of Table 40) could be completely 
utilized for irrigating alfalfa and general field crops on valley lands, and 
with an average net duty of the water of 1.5 acre-feet per acre, the 
supply would be sufficient to irrigate about 36,000 acres, an area larger 
than the total area of these valleys, as shown in the second column of 
Table 40, page 151. In the estimate of the duty of water it is assumed 
that one-half the land is planted in alfalfa and requires 3 acre-feet 
per acre, and that the other half is in general crops requiring 1 acre- 
foot per acre, and that one-third of the water applied in irrigation of 
alfalfa is returned to the ground-water reservoir. For irrigating 
citrus crops on the mesa and foothill lands less water would be re- 
quired to the acre but practically none of it would percolate back to 
the ground-water reservoir. The available supply could not be 
completely utilized on mesa lands, however, by pumping from a few 
groups of wells in each valley for, on account of the configuration 
and shallow depth of the valley fill, complete utilization would require 
many groups of wells and many widely distributed pumping plants 
feeding one or more "booster " plants in each valley. For economic 
reasons the available ground- water supply of the major valley 
therefore can not now be used exclusively in the irrigation of mesa 
lands. It will doubtless ultimately serve a large proportion of the 
arable valley lands, the best agricultural lands along the margins 
of these valleys, and a number of favorably situated blocks of mesa 
land. Data contained in the report of the Conservation Commission 



WATER IN THE MAJOR VALLEYS. 153 

of California 1 show that in 1912 3,050 acres in San Diego County 
were irrigated with water derived from the major valleys. The area 
has been considerably increased since 1912, but the writer's investi- 
gations indicate that in 1915 it did not exceed 8,000 acres. Making 
allowances for inaccuracies in the computations, the writer believes 
that the ground waters of these valleys are adequate to serve much 
more land than has hitherto beer brought under cultivation. 

SAFE YIELD. 

The safe yield of ground-water reservoirs in San Diego County 
for domestic and municipal supplies, as denned on page 154, depends 
on their ability to meet withdrawals during periods of severe drought 
extending over several years during which they may receive little 
or no replenishment. In computing the safe yield the volume of 
water that is normally held in the valley fill and that can be ex- 
tracted during a three-year period was determined, it being assumed 
that no replenishment takes place during this period, that adequate 
replenishment will take place during the next year, and that com- 
plete replenishment will take place before the occurrence of another 
three-year drought. Since safe yield is that required for domestic 
and municipal uses the effect of pumping on the lowering of the 
water table and Jbhe practicable draw down in wells need not be 
considered so carefully as, for reasons of economy, it must be in 
pumping for irrigation. The allowable depression of the water 
table in each valley was estimated from a study of the logs of wells 
(figs. 8, 15, and Pis. XXVI to XXIX), the profiles and cross sec- 
tions (figs. 9-14), and the probable draw down in wells as de- 
termined from pumping tests. The quantity. of water that could 
be drained by pumping from the valley fill was assumed to be 
25 per cent in the upper valleys and 20 per cent in the coastal 
valleys except lower San Luis Key Valley and Santa Margarita 
Valley, where, on account of the large proportion of fine materials, 
15 per cent was considered more nearly correct. Table 41 shows 
the results of the study for each valley, the last column giving the 
approximate annual safe yield in acre-feet. The figures in the 
column headed " Effective area of valley fill" were obtained from 
those in the first column by deducting areas of shallow valley fill 
that will yield little water and areas in which the water probably 
contains so much mineral matter that it is unsuitable for domestic 
uses. In Sweetwater Valley, from which all but local run-off is 
withheld by Sweetwater reservoir, the safe yield as thus computed 
was reduced 50 per cent because the only sources of ground-water 
replenishment are direct rainfall, local run-off, and seepage returned 

1 Tait, C. E., Irrigation resources of southern California: Rept. Conservation Comm. of California, pp. 
29-305,1912. 



154 GROUND WATERS OF WESTERN SAN DIEGO COUNTS, CALIF. 



from irrigation by gravity under the Sweetwater Water Co.'s system. 
The quantities of water indicated by the last column of the table 
could probably be removed from the valleys every year without 
causing serious depletion during long periods of drought. The 
utilization of the water for domestic and municipal supplies reduces, 
of course, the quantity available for irrigation. 

Table 41. — Estimated annual safe yield of ground water available for domestic and 
municipal supplies from major valleys of San Diego County, Calif. 



Valley. 



Area 
under- 
lain by 
valley 

fill. 



Effec- 
tive 
area of 
valley 
fill. 



Assumed 

average 

depth 

water 

table 

could be 

lowered 

by end of 

3 years. 



Per 
cent of 
volume 

that 
could be 
drained. 



Total 

volume 

extracted 

by 

pumping 
during 
3-year 
period. 



Approximate 

annual 

safe yield. 



Acre- 
feet. 



Million 
gallons 
per day. 



Santa Margarita 

San Luis Rey (upper) 
San Luis Rey (lower). 

SanPasqual 

San Dieguito 

San Diego (upper) 

Mission 

Sweetwater (upper) . . 
Sweetwater (lower). . . 
Tia Juana 



Acres. 
3,640 
4,376 
3,270 
1,880 
2,210 
3,120 
2,470 
1,065 
1,532 
4,380 



Acres. 
1,820 
3,060 
1,635 
1,320 
1,220 
2,180 
1,480 
750 
920 
2,630 



Feet. 



A cre-feet. 
13, 700 
23,000 
12, 300 
13,200 
7,300 
16, 400 
8,880 
5,620 
5,500 
23,700 



4,570 
7,640 
4,100 
4,400 
2,430 
5,470 
2,960 
1,870 
1,100 
7,900 



4.1 
6.8 
3.7 



7.1 



27,943 



42,470 



37.9 



For large single projects, for either domestic supply or for irriga- 
tion, the ground-water reservoirs can be used most advantageously 
in connection with surface-water reservoirs that intercept and hold 
the winter run-off. Indeed the relatively small yield of the ground- 
water reservoirs makes such procedure imperatively necessary. 
The principal advantage of the procedure, other than that of increas- 
ing the supply, is that the ground-water reservoir provides a depend- 
able reserve which is free from loss by evaporation or catastrophe 
and, for the most part, from danger of pollution, which can be 
drawn upon heavily in emergency, and which is available after the 
surface reservoirs have been polluted or depleted by extended drought. 
If the cost of pumping is not great, the operation of the pumps to 
full capacity during the period of river flow will save the surface 
water held in storage without depleting the ground- water storage, the 
effect being that of increased diversion from the stream. This method 
also has the advantage of providing a clear, potable water at a time 
when surface waters are likely to be turbid. 

There is a popular belief, which is held even by some engineers, 
that wells in the valley fill draw from a large underground stream 
that follows more or less closely the course of the river channel and 
maintains the level of the ground-water surface under adjacent 
lands by lateral percolation. According to the popular conception, 



WATER IN THE MAJOR VALLEYS. 155 

this stream, although perhaps not moving so rapidly as a surface 
stream, has a very noticeable velocity, and the withdrawal of water 
at any point by pumping from a well is equivalent to a diversion 
from a surface stream and reduces the volume of underflow and the 
supply available to other wells downstream. The writer's investi- 
gations, however, indicate that such a belief is entirely unwarranted. 
As has already been shown (see p. 148) the ground water in the valley 
fill moves downstream very slowly, the measured advance at a narrow 
cross section where conditions were favorable for rapid movement 
being only one- third of a mile a year. The ground water, in fact, 
occupies a series of reservoirs represented by the valley fill and does 
not move in distinct streams any more than does the water in a 
surface reservoir or lake. When filling of these reservoirs ceases, 
late in the spring, there is a very slow general movement of water 
from the upper toward the lower part of each reservoir, but there is 
no particular segregation into bodies of moving and standing ground 
water, and certainly there is no continuous underflow through the 
basins. The effect of pumping from a well in the valley fill is indi- 
cated by the lowering of the water level in the vicinity of the well, 
just as pumping from a surface reservoir lowers the water level. 
The lowering does not, however, occur over the whole surface of an 
underground reservoir but is confined to a circle whose center is near 
the well. The diameter of this circle gradually increases if heavy 
pumping is carried on without intermission, and during the course 
of a long pumping season the circle of influence may extend out 
1,000 feet or more from the well. The effect of intermittent pumping, 
however, does not extend far from the well, as the circle of influence 
shrinks when pumping ceases. The only wells that are affected by 
pumping are those within the circle of influence. The lowering of 
the water table that occurs around a well during any pumping 
season will normally be counteracted during the following winter by 
replenishment of the local ground-water supply from precipitation 
and run-off, so that the effect of the previous season's pumping is 
thus entirely overcome. It is therefore obvious that the effect of 
pumping is confined to the vicinity of the well from which water is 
drawn and is not a diversion from an underground stream on which 
all lower wells are depending for their supplies. 

YIELD OF WELLS. 
CONDITIONS AFFECTING YIELD. 

The yield of wells in the fill of the major valleys of San Diego 
County depends mainly on (1) the capacity of the material of the 
water-bearing stratum to transmit water, (2) the thickness of the 
water-bearing stratum, (3) the drawdown, or lowering of the water 
level in the well during pumping, (4) the size and shape of the well, 



156 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

and (5) the length and kind of the screen or perforated area and the 
methods of cleaning and developing the well. 

The capacity of the material of the water-bearing stratum to trans- 
mit water — the condition having the greatest effect on the yield of 
wells — depends mainly on the effective size of grain and on the 
porosity of the water-bearing material. Experiments have shown 
that the flow of water through any material varies as the square of 
the effective size of grain; hence doubling the effective size of grain 
will quadruple the flow of water. Likewise, the flow of water is 
also greatly increased with an increase in porosity. The alluvial 
materials composing the valley fill in San Diego County are made up 
of particles nonuniform in size, the smaller filling the voids or 
spaces between the larger. The porosity of such materials is much 
smaller than that of a material composed of particles uniform in 
size. Thus although large boulders or cobblestones scattered through 
a sand or fine gravel increase the effective size of grain they decrease 
rather than increase the transmission capacity of the sand or fine 
gravel, because the decrease in porosity of the material more than 
offsets the increase in effective size of grain. Slichter x has expressed 
the capacity of a water-bearing material to transmit water by means 
of a coefficient whioh he has termed the " transmission constant/ 7 
This constant varies mainly with the size of grain and the porosity 
of the material and is defined as the quantity of water, in cubic feet, 
that is transmitted in one minute through a cylinder of material 1 
foot long and 1 square foot in cross section, under a difference in 
head at the ends of 1 foot of water. Other things being equal, the 
yield of a well is directly proportional to the transmission constant 
of the water-bearing material. 

In its effect on yield the thickness of the water-bearing stratum is 
closely allied to its transmission capacity. If the water-bearing 
strata penetrated in two wells are of the same material, the well in 
which the water-bearing material is thickest will yield the greater 
quantity of water, provided, of course, that the casing of the well 
permits the water to enter along the entire depth of the stratum. 

Nearly equal to transmission capacity in its effect on yield of wells 
is the lowering of the water level during pumping, for the amount of 
lowering, or the " drawdown/' determines the head under which 
water flows into the well. Other things being equal, the yield of a 
well varies directly with the drawdown. If, however, the drawdown 
is so large that the water level is forced below the top of the intake 
of the well, the resulting decrease in area available for the entrance 
of water obviously affects the yield and changes the relation. The 
amount of drawdown is specially significant in shallow wells, where 

1 Slichter, C. S., The rate of movement of underground waters: U. S. Geol. Survey "Water-Supply 
Paper 140, pp 10-15, 1905. 



WATER IN THE MAJOR VALLEYS. 157 

it directly limits the entrance area. The yield of a well will not vary 
directly with the drawdown if an appreciable part of the drawdown 
is due to entrance head. Entrance head represents the pressure of 
water necessary to produce flow through the perforations of the 
well casing and depends on the size and shape of the perforations 
and their freedom from obstructions, as, for example, by particles of 
sand and gravel. The amount of drawdown that is desirable must 
be determined by carefully considering the relation of value of yield 
to cost of pumping. The value of the greater yield obtained by an 
increase in drawdown may be more than offset by the increase in 
the cost of pumping due to the greater lift. The economical draw- 
down in any well can be determined only by studying the local 
conditions. 

Size has greatest effect in shallow wells, which are relatively large 
in diameter as compared with depth, as, for example, in dug wells of 
the pit type. In such wells the yield seems to be directly propor- 
tional to the diameter. In drilled wells, most of which are less than 
12 inches in diameter, the effect of diameter on yield is not so direct, 
but greater diameter permits the water to enter at a lower velocity ; 
thus decreasing the head lost in friction in passing through the 
water-bearing material. If the water-bearing stratum is composed 
of fine material the dependence of yield on diameter of the well is 
much less than is commonly supposed; but if the material is fine 
sand the larger well is more advantageous because,, owing to the 
lower entrance velocity of the water, the well is less likely to become 
clogged with sand. In California 10-inch or 12-inch casing is com- 
monly used in irrigation wells. Some authorities recommend that 
8-inch casing should be the largest used in ordinary irrigation wells, 
but for the conditions usual in California, where the wells are drilled in 
soft material and the price per foot is practically the same for wells 
from 7 inches to 14 inches in diameter, the only advantage of an 
8-inch over a 12-inch well is the difference in the cost of casing, a 
difference that would be comparatively small except for very deep 
wells. The advantages of the 12-inch well over the 8-inch are some- 
what greater yield for the same water-bearing stratum, less likeli- 
hood of clogging through entrance of sand, and greater ease of sinking 
by the methods of drilling ordinarily used. This last advantage is 
particularly great in drilling in formations containing cobbles or 
boulders, in which it may be impossible to use casing smaller than 
12 inches in diameter. The use of casings as large as 16 to 24 inches 
in diameter is usually advantageous only where the water-bearing 
material is very coarse and it is not recommended for wells in San 
Diego County. 

The area and design of the screen affect the yield of a well because 
of the head lost through entrance of water into the well. If the 



158 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

screen is clogged, or if the perforations are not ample the yield is 
decreased. Other conditions remaining the same, the yield of a 
well will be increased by installing a screen or putting in perforations 
designed to reduce the entrance head as much as possible; at the 
same time clogging of the well must be prevented. 

TESTS OF YIELD OF WELLS. 

PURPOSE AND METHODS OF TESTS. 

The best method of estimating the probable yield of a well before 
it is sunk is from tests of wells sunk in the same neighborhood or in 
similar formations. The nearer the position of the prospective 
well to the tested well the closer can its yield be estimated, because 
of the greater probability that it will penetrate similar water-bearing 
strata. If the prospective well is not near a tested well its probable 
yield can best be estimated from tests of wells sunk in formations 
of the same type. 

The yield of wells can not be compared directly unless their draw 
down is the same. To make such a comparison it is necessary to 
determine for each well its "specific capacity," or the quantity of 
water furnished by the well for a unit lowering of the water level in 
the well by pumping. Specific capacity is usually expressed in 
gallons per minute per foot of draw down. For wells which are 
similarly perforated and which penetrate similar water-bearing 
strata the specific capacities will be found about the same. The 
specific capacity of wells, determined by test, is the best index of 
the yield of proposed wells drawing from the same formation. 

Another term used in expressing the yield of wells is the "specific 
capacity of the formation." It is defined as the yield in gallons per 
minute per foot of drawdown for each square foot of perforated or 
strainer area, and it is perhaps a more accurate term for comparing 
the yield of wells than "specific capacity/' as it takes into account 
the available area for entrance of the water. 

Many of the wells that have been drilled in San Diego County do 
not yield as much water as they would if they had been properly 
constructed, and in order that those who contemplate sinking wells 
may benefit by the knowledge already gained, the writer made 
pumping tests to determine the yield and the specific capacity of 
several typical wells. In each of the tests the installed pumping 
equipment was used, and the runs were continued until the draw- 
down ceased to increase. Most of the tests covered an hour or more. 
The discharge from the pump was measured with a 2-foot Cippoletti 
weir, with a current meter, or with a tank of known dimensions. 
The drawdown was measured with a tape or was estimated from the 
vacuum gage readings after making due allowance for head lost in 
the suction lines. 



WATER IN THE MAJOR VALLEYS. 159 

RESULTS OF TESTS. 

Well KJf.1. — The pumping plant owned by C. A. Van Houten, in 
Mission Valley, about 3 miles northeast of San Diego, comprises 
five drilled wells, 60 feet apart, connected with the same pump. 
Each well is provided with 10-inch standard screw casing sunk to 
an average depth of 80 feet. The principal water-bearing stratum is 
fine, clean gravel, between the depths of 70 and 80 feet. The section 
of the casing that penetrates the water-bearing stratum is perforated 
with drilled holes. (For logs of wells see PI. XXVIII.) The normal 
water level in the wells varies during the year from 6 to 8 feet below 
the surface, and at the time of the test was about 8 feet. 

During the test, which lasted five hours, the wells were pumped at 
the rate of 614 gallons a minute. The drawdown was estimated at 
22 feet, which carried the water level to about 30 feet below the sur- 
face. The yield of each well was therefore about 6 gallons per minute 
per foot of drawdown or, for a perforated area of 131 square feet, 
about 0.21 gallon per minute per foot of drawdown for each square 
foot of perforated area. The low specific capacity of these wells 
suggests that they were not drawing freely from the water-bearing 
stratum. 

Well L 82. — The pumping plant owned by J. Johnson, jr., in the 
upper San Diego River valley, about 3 miles west of Lakeside, com- 
prises 10 drilled wells, 60 feet apart, interconnected to the same 
pump. In each well 12-inch double stovepipe casing is sunk to an 
average depth of 60 feet. The log of the wells (PL XXIX) shows 
that the principal water-bearing stratum extends from 10 feet below 
the surface to 60 feet below the surface. The normal water level 
in the wells ranges during the year from about 8 feet to 12 feet below 
the surface, and at the time of the test was about 8 feet below. 

The wells were pumped 48 minutes at the rate of 2,475 gallons per 
minute. The full drawndown, estimated at 12 feet (making the 
water level 20 feet below the surface of the ground) was reached 
almost immediately after pumping was started. The yield of each 
well was therefore about 21 gallons per minute per foot of drawdown 
or, for an estimated perforated area of 400 square feet, about 0.53 
gallon per minute per square foot of perforated area. 

Well 132. — The pumping plant owned by C. M. Richardson, in 
sec. 34, T. 18 S., R. 2 W., in Tia Juana Valley, about 2 miles south- 
east of Nestor, comprises two drilled wells, 72 feet apart, connected 
to the same pump. In these wells 12-inch casing is sunk to a depth 
of 68 feet, the last 17 feet in gravel, which is the principal source of 
the water. (For logs of wells see PL XXVI.) The lower ends of 
the casings are perforated along a length of 12 feet. The water level 
in the wells, according to the owner, is normally 9 feet below the 
surface of the ground. 



160 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

For a period of one hour the wells were pumped at the rate of 
1,120 gallons per minute. During the first 15 minutes the water 
level was drawn down an estimated distance of 27 feet below its 
normal level, or 36 feet below the surface of the ground, where it 
remained to the end of the test. Each well yielded, therefore, a 
little more than 20 gallons per minute for each foot of drawdown, or 
about 0.55 gallon per minute per square foot of perforated area per 
foot of drawdown. This well appears to be typical of wells in Tia 
Juana Valley, which penetrate the gravel that underlies most of the 
valley at depths ranging from 50 to 75 feet (figs. 9 and 10, pp. 112, 113). 

Wells at Mission Valley pumping plant of San Diego city. — The 
wells at the Mission Valley pumping plant owned and used by the 
city of San Diego for municipal water supply were tested for yield 




Well 



Standpipe 



Pipe line 
Figure 16.— Plan of Mission Valley pumping plant of the city of San Diego. 

from November 16 to December 27, 1914, by H. A. Whitney, hydraulic 
engineer cf the city water department. The tests are reported here 
because they furnish additional information as to the yield of wells 
in Mission Valley. The only test made by the writer in this valley 
was that on well K41 (p. 159), whose yield is apparently not repre- 
sentative of that which should be expected from wells that penetrate 
the gravel underlying this valley. 

The relative positions of the city wells are shown in the sketch map 
forming figure 16 and the logs of the wells in Plate XXVIII (p. 116). 
The principal water-bearing stratum in each well is gravel and ranges 
in thickness from 5 to 16 feet. In some of the wells, notably in well 
K 90, the stratum of gravel from which the water is drawn contains 
some clay, and wells K 93, K 96, and K 91 draw partly from such a 
formation. These drilled wells are lined with 12-inch stovepipe 
casing and are perforated where they pass through the water-bearing 



WATER IX THE MAJOR VALLEYS. 



161 



stratum. Each well was equipped with a pump. The results of the 
tests and the computations of specific capacity are given in Table 42. 
The drawdown recorded in the table was reached about 10 minutes 
after pumping was started in all the wells except K 105, in which the 
maximum drawdown was reached in about 20 minutes. For many 
of the wells the length of the perforated casing was not known, but 
for these it was assumed to equal the thickness of the water-bearing 
stratum, and that asumption was used in computing the specific 
capacity of the gravels. 
Table 42. — Summary of tests of San Diego city wells at Mission Valley pumping plant. 



[Tests made Nov. 16 to Dec. 27, 1914, by H. A. Whitney, hydraulic engineer, Department of Water, 






city of San Diego.] 
























Specific 


















capacity 














Specific 




of gravels 














capacity 
of well 
(gallons 


Area of 


(gallons 




Duration 


Total 

depth of 

well 

(feet). 


Thick- 
ness of 


Draw- 


Total 
yield 


perfo- 
rated or 


per 
minute 


Well No. 


of test 


water- 


down 


(gallons 


per 


strainer 


per foot 




(hours). 


bearing, 


(feet). 


per 


minute 


surface 


of draw- 






stratum. 




minute). 


per foot 


(square 


down per 














of draw- 


feet). 


square 














down). 




foot of 
strainer 
surface). 


K 93 


24 
24 
24 
24 

24 
24 


90 
82 
80 
80 
80 
80 


08 
15 
all 
12 
12 
14 


18.50 
12.80 
25.40 
10.40 


477 
477 
432 
477 
477 
477 


25.8' 
37.2 
17.0 
45.9 


25.1 
56.6 
47.2 
37.7 
25.1 
44.0 


1.027 


K 95 


.658 


K 96 


.360 


K 100 


b 1. 219 


K 102 




K97 


12.70 


37.6 


.855 


K 94 


24 

24 

. 24 


58 
60 
75 


9 

12 

oil 


11.60 
16.20 
30.10 


504 
504 
407 


43.5 
31.1 
13.5 


28.3 
37.7 
15.7 


6 1.538 


K 92 


6.825 


K 91 


6.860 


K 90 


24 


45 


7 


24.20 


477 


19.7 


22.0 


6.896 


K 105 


24 


80 


12 


33.50 


369 


11.0 


25.1 


.439 







a Gravel, 5 feet; remainder gravel and clay. 

6 Figures obtained by assuming the length cf perforated area equal to the depth of water-bearing stratum . 

The records show clearly that wells sunk near each other in the fill 
of the major valleysmay differ greatly in yield. For example, wellK 100 
yielded nearly 46 gallons per minute per foot of drawdown, whereas 
K 105 yielded only 11 gallons per minute per foot of drawdown, 
though each well, according to the driller's log, penetrated 12 feet of 
gravel. Other variations in yield are almost as striking. As the 
wide difference in yield between wells K 100 and K 105 can not be 
ascribed entirely to differences in the gravel stratum, it must be con- 
cluded that well K 105 was, for some reason, not drawing freely from 
the gravels. Employees in charge of the pumping plant report that 
well K 105 has always produced poorly. 

The specific capacity of the gravels in the water-bearing formations 
of Mission Valley, as expressed by the yield of the wells in gallons per 
minute per foot of drawdown per square foot of perforated area, is 
shown in Table 42 to vary from 0.360 to 1.538. The lowest capacity 
was obtained in the test of well K 96, which passed through only 5 feet 
of gravel and draws partly from a formation including gravel and clay. 
115536°— 19— wsp 446 11 



162 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



DISCUSSION OF WELL TESTS. 



A summary of the results of tests for yield of wells in the fill of the 
major valleys of San Diego County, including the observations and 
the computations of specific capacity, is given in Table 43. Ke- 
sults obtained from tests of the San Diego city wells in Mission Valley 
are recorded in Table 42. 

These tests show in general the dependence of yield on the character 
and thickness of the water-bearing material. The specific capacity 
of the wells tested ranged from 6 to 45 gallons per minute per foot of 
drawdown. The smallest and largest yields were obtained from wells 
K 41 and K 100, respectively , which are in Mission Valley and are only 
about 2 miles apart and which draw their water from gravels that are 
similar in character and thickness. The great difference in yield is 
probably due to clogging of well K 41, so that water from the gravels 
does not enter freely. Clogging no doubt also accounts for the low 
specific capacity — only 1 1 gallons per minute — of well K 105, in which, 
according to the driller's log, the stratum of gravel is as thick as in 
well K 100 (PL XXVIII). All the other wells tested in Mission Valley 
yielded more water than either well K41 or K 105, though many of 
them, according to the driller's logs, draw water from strata inferior 
to those supplying K 41 and K 105. Except for these two wells the 
tests indicate that the specific capacity of the wells depends on the 
character and thickness of the water-bearing strata, being largest for 
wells that draw water from the thickest and most open gravels. 

Table 43. — Summary of tests of typical wells in San Diego County. 

Wells in fill of major valleys. 



Well 
No. 


Owner. 


Location. 


Formation. 


Thick- 
ness 
of 

water- 
bearing 
strat- 
um 
(feet). 


Draw- 
down 
(feet). 


Total 
yield 

(gallons 
per 

minute). 


Specific 
capac- 
ity of 
well 
(gallons 

per 
minute 
per foot 

of 
draw- 
down). 


Area of 
perfo- 
rated 
or 
strainer 
surface 
(square 
feet). 


Specific 
capac- 
ity of 
grav- 
els. « 


0132 
K41 

L82 


C.M.Richardson.. 
C A. VanHouten. 
J. Johnson, jr 


Tia Juana Val- 
ley. 
Mission Valley. 

Upper San 
Diego River. 


Valley fill. 

do 

do.... 


17 

10 
50 


27 
22 
12 


a 1,120 

6 614 

c2,475 


20 

6 

21 


75.4 
dl31 
<*400 


0.55 
d0.21 
d0.53 


Wells on Nestor and Chula Vista terraces. 


Olio 


W.E.Williams.. 
Tucker & Evans.. 
R.J.Jaeger 


Tia Juana Val- 
ley. 
2 miles west of 

Nestor. 
One-half mile 
east of Nestor. 


San Diego 

formation. 

do 

...do 


3 
14 


15.25 

21 

none. 


231 
373 
116.5 


15 

18 






O 47 






O 102 








I 








Wells in residuum. 


L24 


,T. Miller 


1 mile north of 

El Cajon. 

2 miles east of 
El Cajon. 


Residuum. 
do 


32 

62.5 


20.8 
24.7 


156 
79 


7.5 
3.2 






L98 


Chas. Bentley 







o2 


wells. c io well 
wells. <* Estima 


s. « Gallons i 
ted. 


>er minute o 


drawdc 


wn per £ 


quare fo 


ot of strt 


liner sur 


face. 



WATER IN THE MAJOR VALLEYS. 163 

The specific capacity of the water-bearing materials is shown by . 
the tests to vary from 0.21 to 1.538, thelarger capacities being found, 
as before, in wells drawing water from the more open and thicker 
gravels, although a few exceptions may be noted. On the whole, the 
specific capacities of these gravels may be said to be high, for in many 
sections of the country a yield of 0.33 gallon per minute per foot of 
drawdown per square foot of perforated area would be considered 
good. 

The tests indicate that wells sunk in the major valleys of San Diego 
County, penetrating a considerable depth of coarse sand or from 10 to 
15 feet of open gravel, such as lies at the bottom of the ancient river 
valleys, if properly perforated or equipped with strainers, may be ex- 
pected to yield at least 20 gallons per minute per foot of drawdown. 
Where conditions are most favorable — that is, where the well passes 
through open gravel more than 10 feet thick and the casing is skill- 
fully perforated— the specific capacity may amount to at least 30 gal- 
lons per minute per foot of drawdown; where conditions are poor — 
where the water-bearing formation contains little or no gravel and 
only a moderately thick stratum of coarse sand and the perforations 
are too large, too small, or too few — the specific capacity of the wells 
may be considerably less than 20 gallons. For a drawdown of 10 feet 
in drilled wells provided with 10 or 12 inch casing, a very good well 
should yield 300 gallons per minute or more, an average well 250 gal- 
lons per minute, and a poor well less than 200 gallons per minute ; for 
a drawdown greater or less than 10 feet the total yield would be pro- 
portionally larger or smaller if other conditions remained the same. 

The drawdown to be assumed in estimating the yield of wells 
depends on the relation of yield desired to the saving in cost to be 
effected and should be carefully computed for each pumping plant. 
A drawdown as great as 20 feet will rarely be found profitable. If 
the estimated yield of a single well for a moderate drawdown is too 
small, the desired yield can perhaps best be obtained by sinking two 
or more wells, 60 to 100 feet apart, and connecting them with the 
same pump. Pumping plants of this type are very common in the 
valley areas and are usually successful. For example, if the specific 
capacity is estimated at 20 gallons per minute, a total yield of 400 
gallons per minute may be obtained either from a single well with 
20-foot drawdown or from two wells with a drawdown of about 10 
feet, allowance being made for a small additional drawdown to coun- 
teract interference. The choice must be based on comparison of the 
I annual cost of pumping and the interest on the cost of sinking the 
well or wells. 

The practical difficulty of closely estimating the yield of a well 
before sinking it must; however, be clearly remembered. Though 
the material composing the fill of the major valleys is fairly uniform 



164 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

in character and distribution, the logs of individual wells show marked 
variations, some of them within rather short distances; therefore the 
probable yield can be only roughly estimated. In other words, the 
generalized figures given in the preceding paragraphs are intended 
for use only as a guide. 

METHODS OF SINKING WELLS. 

The common method of sinking wells in the major valleys of San 
Diego County is the well-known California or stovepipe method, 1 
which is well adapted for use in the loose sand and gravel (in few 
places exceeding 100 feet in thickness) that form the water-bearing 
strata in these valleys. Good wells range in depth from 50 to 100 
feet, except in the lower part of San Luis Rey Valley and possibly oi 
Santa Margarita Valley, where the valley fill in places exceeds 200 
feet in thickness and the best wells are 160 to 210 feet deep. 

No particular difficulty is experienced in drilling, although in some 
places beds of cobblestones and boulders, that are hard to penetrate, 
are encountered at the bottom of the valley fill. Such beds are usually 
open, however, and yield water so freely that there is seldom any 
reason for drilling through them. In Tia Juana Valley a number of 
very good wells draw their entire supply from such a bed at the bottom, 
the casing being without perforations. It is customary, however, to 
perforate the well casing at all strata of coarse sand and gravel in 
order to increase the yield. The perforations consist of vertical slits 
from three-sixteenths to five-sixteenths inch wide and about 8 inches 
long. The cuts are made with a knife that is thrust through the 
casing at the position desired and then slowly drawn upward the 
desired length with hydraulic jacks. For wells entirely in fine sand 
or material which does not readily yield water, it has been found 
possible to increase the yield greatly by running coarse gravel down 
around the outside of the casing. This is done by depositing the 
gravel around the casing at the surface, and then withdrawing 
material from the bottom of the casing with the sand bucket. The 
sand around the casing gradually settles, carrying the gravel down 
with it. There is thus created around the well a cylinder of coarser 
material which, when the casing is perforated and the well cleaned, 
gives a greatly enlarged percolating surface and also prevents fine 
material from entering the perforations and clogging the well. Wells 
which would be classed as failures have by this method been made to 
yield as much as those in more favorable formations. An experi- 
enced local driller who has used this method extensively states that 
it is not wise to employ it where the casing passes through one or 
more layers of clay in the sand, as the clay has a tendency to plaster 
the outside of the casing and shut out the water. 

1 Slichter, C S., The rate of movement of underground waters: U. S. Geol. Survey Water-Supply 
Paper 140, p. 98, 1905. 



WATER in the ma joe valleys. 165 

Prices for well drilling by this method vary somewhat, depending 
on the local conditions and the cost of well casing. In August and 
September of 1914 a number of wells were put down in Mission 
Valley for the city of San Diego by Mr. A. H. Hatherly, a local driller, 
who has had more than 10 years' experience in San Diego County. 
The contract price was $2.95 per foot for ordinary material and $4 
per foot for boulders or rock. A charge of $15 per day additional 
was made for perforating, cleaning, and similar work. The price per 
foot included 12-inch stovepipe casing at $1 per foot. The average 
cost to the city of five of these wells 80 feet deep, sunk mostly in sand 
and gravel, and perforated with 40 to 90 cuts five-sixteenths inch by 
8 inches was $263. The prices are typical of similar wells in other 
parts of this valley and in such valleys as Tia Juana, where most of 
the wells are about 80 feet deep. In the low mesa immediately 
north of Tia Juana Valley the cost of drilled wells 35 feet deep is 
almost as great as that of deeper wells in the valley on account of the 
formation, which consists of gravel and cobblestones cemented with 
clay. The prices will differ with the changes in the price of well 
casing, which varies with general market conditions and has advanced 
very much since these wells were sunk. 

The casing commonly used for wells in the valley fill is the double 
slip-joint or stovepipe casing made of lap-riveted cylinders of sheet 
iron or steel. The cylinders are in 2-foot lengths and are of two 
sizes, one fitting inside the other. The larger sizes overlap the 
smaller by 1 foot, thus breaking the joints. The size most generally 
used is 12 inches in diameter and is made of No. 14 gage metal. 

A casing of unusual type, devised by Mr. G. M. Hawley, of Jamacho, 
was found in recently constructed wells in the upper Sweetwater and 
San Diego Eiver valleys. The casing is made of long strips of 
surfaced redwood nailed together with spacers so as to form a long 
open cylinder with many narrow slits extending full length, except 
where interrupted by the spacers at intervals of about 3 feet. The 
cross section of the strips was trapezoidal, the dimension varying 
somewhat with the size of casing. A specimen of 10-inch casing 
examined by the writer was composed of 32 staves, 1 inch thick, 
with edges three-fourths and one-half inch wide. The strips were 
placed with the three-fourths-inch face outward, and half-inch face 
inward. The outside width of the slits is varied to suit the formation, 
and in several wells examined by the writer it was only one-sixteenth 
inch. In some wells the outside of the casing is wrapped with Copper 
wire or screen. The casing is manufactured at El Cajon, the price in 
1914 being $1 per foot. The casing was devised to increase the 
percolating area of the well without cutting the relatively wide slits 
necessary in perforating metal casing with a knife and at the same 
time to avoid the more costly metal screens. In using this casing a 



166 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, (ALIF. 

metal casing of larger diameter is first driven down and the wooden 
casing is dropped inside the metal casing, which is then removed. 
The casing is being used in wells not more than 50 feet deep sunk in 
sand and fine gravels and is not adapted for use in silt, which enters 
the slits and clogs the well. It has not the strength and durability 
of a metal casing, but seems to be filling a local need very satisfactorily. 

WATER IN THE MINOR VALLEYS. 

By A. J. Ellis and 0. H. Lee. 
DISTRIBUTION OF MINOR VALLEYS. 

In the broad tracts of the coastal belt between the deeply filled 
canyons of the major streams the principal sources of ground water 
are the relatively thin and narrow deposits of valley fill that cover 
the floors of many of the minor valleys. In the highland area, also, 
some of the minor valleys contain deposits that are capable of 
furnishing water. The supplies obtainable from these deposits, 
therefore, although meager compared with those obtainable from 
the fill of the major valleys, are nevertheless exceedingly valuable, for 
most of the valleys are bordered by large areas in which it is very 
difficult to obtain satisfactory supplies. 

The distribution of the minor valleys is shown on the topo- 
graphic maps published by the United States Geological Survey. 
The San Diego, La Jolla, Oceanside, Escondido, and El Cajon maps 
cover the coastal belt and western parts of the highland area and 
show by means of contour lines representing 25-foot intervals the 
widths of the valley floors and their depths below the levels of the 
mesas; the scale of these maps is about 1 mile to the inch (1 :62,500). 
The Capistrano, San Luis Rey, Ramona, and Cuyamaca sheets also 
cover the highland area and parts of the coastal belt, but their scale 
is about 2 miles to the inch (1 :1 25,000) and their contour interval is 
100 feet. The map forming Plate II shows all these valleys, but on 
account of its small scale and large contour interval it shows little 
of the detail of width and depth. 

The streams of the minor valleys of the coastal belt rise within 25 
miles of the ocean, either on the coastal belt itself or on the first 
prominent mountain slopes, and they drain the areas between the 
major valleys. The largest, named in order from north to south, 
are Arroyo San Mateo, Arroyo San Onofre, and Las Pulgas, Buena 
Vista, San Marcos, Escondido, McGonigle, Soledad, San Clemente, 
Las Choyas, and Otay creeks (Pis. XV, XX, XXIII, and XXV). 

The largest of the minor valleys in the highland area are Escondido 
Valley, along Escondido Creek, the valley of Santa Maria Creek, the 
upper part of the valley of San Luis Rey River, in Warner Valley, 
and the valley of Los Penasquitos Creek in Poway Valley. 



WATER m THE MltfOR VALLEYS. 167 

Many of the minor valleys are very attractive for residence and 
contain tracts of bottom land well adapted to raising field crops or 
vegetables and to dairying. In many places these bottom lands 
have been brought under cultivation and irrigation by means of 
water from the underlying valley fill. The lands of the upper 
slopes and foothills in the highland valleys, such as Escondido and 
El Cajon valleys, are adapted to citrus culture, and where surface 
water is available for irrigation orchards have been planted. 
Although most of these valleys are small and widely scattered, 
they contain in the aggregate considerable agricultural land. 

MINOR VALLEYS OP THE COASTAL BELT. 
TOPOGRAPHY. 

The minor valleys of the coastal belt extend back from the coast 
6 to 8 miles, range in width from 200 feet to half a mile, and are 
connected with the level mesas by steep slopes 200 to 400 feet high. 
They slope downstream at rates ranging from 20 to 40 feet per 
mile, but in most places are level transversely. In area they seldom 
exceed a few hundred acres. They are underlain and bordered by 
sedimentary rocks. 

MATERIALS OF THE FILL. 

All the minor valleys contain alluvium and other fill in their 
lower but not in their upper parts. The fill is composed of mate- 
rials washed in from the mesas in times of heavy rainfall and of 
similar materials which are blown into the valleys by the strong 
winds that at certain times of the year sweep the mesas. Most 
of it is rather coarse though poorly assorted, and water passes 
through it freely. It is inclosed on the sides and bottom by for- 
mations that contain little or no water above sea level and that 
apparently do not absorb water so readily as the fill itself. These 
minor valleys may therefore be regarded as rather steeply inclined 
troughs partly filled with loose material through which the drainage 



The quantity of water that can be obtained from a well in the 
fill of a minor valley depends on the thickness of the fill, the depth 
of the valley floor below the top of the mesa, and the distance of 
the well from the mouth of the stream. In most of the valleys 
the fill is deepest and broadest farthest below the mesa level and 
is most highly water bearing near the mouths of the valleys, and 
it gradually diminishes in depth, breadth, and water-bearing capacity 
toward the heads of the valleys. It is probably not more than 50 
feet thick in any of the minor valleys. 



168 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

WATER TABLE. 

The water table in the minor valleys of the coastal belt lies farther 
beneath the surface than in the major valleys. In general shape 
and position, however, it corresponds to that in the major valleys, 
having little slope across the valleys but an appreciable slope down- 
stream. Its fluctuations within each year are similar to those in 
the major valleys of the coastal belt but of wider range (Pis. XLIII 
and XLIV). The fluctuations from year to year are also probably 
greater than in the major valleys, owing to the small run-off during 
dry years. 

Observations of ground-water level were made at well K 106, 
in Murphy Canyon; K 86, in Murray Canyon; K 117, at the mouth 
of Sycamore Canyon; K 115, in the fill of a small canyon entering 
upper San Diego River from the south and a little west of Sycamore 
Canyon; and B 10, at the mouth of a tributary entering San Luis 
Rey River from the north between Bonsall and Mission San Luis 
Rey. A study of water level was also made at six wells in Otay 
Valley, the largest of the minor valleys of the coastal belt — Nbs.' 
O 90, O 42, 87, O 38, O 41, and O 91— during the season of 1914-15. 
The position of all these wells is shown on Plate XX and the wells 
are fully described in Table 45. A summary of dates of maximum 
and minimum water level and the range of fluctuation is given in 
Table 32 (p. 133). Details, of the observations at wells K 106, K 86, 
K 115, and B 10, at well L 78 at Lakeside, in El Cajon Valley, and 
of wells O 99, O 87, and O 41 are shown graphically in Plate XLIII, 
A profile of the water table along the line D-D of Plate XX is 
shown in Plate XLIV, but this profile, although drawn for Otay 
Valley, does not show the ground-water profile in the valley fill 
but in the San Diego formation to the north. In order to indicate 
the relations of the ground-water surface in these two adjacent 
formations, two cross sections of the valley are shown in Plate 
XLIV— one at wells O 42 and O 97, the other at wells O 96, O 95, 
and O 40. These two diagrams illustrate the greater fluctuation 
of the water table in the valley fill and its elevation compared with 
that in the adjacent Tertiary formations. The conditions indicated 
by these diagrams are typical of those found in the minor valleys of 
the coastal belt. 

GROUND-WATER YIELD. 

The quantity of ground water available in the minor valleys of the 
coastal belt is small, owing to the narrow width and shallow depth 
of the fill and the small run-off and short period of flow of the streams 
that traverse the valleys. Supplies adequate for domestic use can, 
however, be obtained in most of them. The safe yield of most of 
the wells is very small because the run-off in dry years is almost 



PLATE XLIH 



393 

392 
J 9/ 
390 
389 
388 
387 




135 
/34 
133 
132 
131 
130 
iZ9 

he 

K7 



WELL K I06 

Ex Mission San Diego, 1560 ft.N. oi 
Diego River in Murphy Canyon. Qg 
bridge, elevation s 68.0ft. 



WELL K 86 

Ex Mission San Diego 900 ft. N. c 
Diego River, 75 ft.W.of creek ai 
of Murray Canyon, Dug well, ele 
34.8 ft 



WELL O 99 

N w. Usee. 20, T. IdS., R. I. W., or, 
of Otay River. Dug well, e/era, 
139.00 ft. 



Oct. 



Nov. 
1914 



Dec. 



LEYS. 



U. S. GEOLOGICAL SURVEY 



WATER-SUrri.1 



446 PLATE XT.TTT 





Oct 


191* 1 
Nov. Dec. 1 Jan. | /T;4. 


Mar. 


T-A5F- 


■y-mv- 


1915 




"I 






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El Cajon Land Grant, 1120 ft 5. of San Diego y^ 
Diver. Drilled wellsz.Bft. deep, elevat onf 












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levation 68.0 ft. 


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anyon 75 




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,>n Diego 900 ft. 

•sft.tv.ofcreek 


at mouth 












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elevation 


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lit 
































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Jan. 


Feb. 


Mar. 


Apr. 


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Joly 


Aug. 


















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DIAGRAMS SHOWING FLUCTUATION OF WATER ' rABLE m OBSERVATION WELLS IN FILL OF MINOR VALLEYS. 



WATER IN THE MINOR VALLEYS. 169 

negligible. The use of ground water for irrigation in these valleys 
must as a rule be restricted to lands on the floors of the valleys, but 
even with this restriction the supply in many places will be insufficient 
to serve all the overlying land, particularly in- dry years. The largest 
and most permanent yields will be obtained from wells sunk in the 
deepest and widest parts of the valleys that are traversed by the 
larger streams having the longest periods of flow, but they will be 
much smaller than the yields of good wells in the major valleys of 
the coastal belt. The best sites for wells are near stream channels 
and in places where the fill is deepest, but care must be taken to 
protect wells and pumping plants from damage by floods. Wells 
sunk too near the mouths of valleys that open to the ocean may yield 
salt water ; consequently well sites should be chosen far enough from 
the ocean and from the lagoons and salt marshes along the shore to 
avoid the effects of backwater that during long droughts extends some 
distance inland. 

Both for domestic use and for irrigation where the valley fill is very 
thin or absent dug wells of large diameter are likely to be the most 
satisfactory, because of their storage capacity and because the large 
area of wall surface permits rapid infiltration of water into the wells. 
Where the known thickness of the fill justifies drilling, drilled wells may 
be used to advantage, but where the fill is shallow it is wiser not to 
depend on the water that may be found in the fill but to drill deep 
enough to obtain a supply from the underlying Tertiary beds. 
Deep drilling should not be attempted, however, except where the 
valley floors are 200 or 300 feet below the level of the mesa. The 
usual practice, where the fill is 25 feet or more in depth, is to sink 
small cased wells, 6, 8, or 10 inches in diameter. The largest and 
most permanent supply at any single pumping plant will be obtained 
by sinking several small wells at intervals of 75 to 100 feet, and the 
largest and most reliable aggregate supply from one of the minor 
valleys will be obtained by installing a number of small plants rather 
than a few large ones. 

At present wells in the minor valleys are widely separated and there 
is little danger of contamination of well water except from some 
local source. If, however, as is likely, settlements should increase 
in the valleys or on the adjacent heights, considerable care must be 
exercised to protect domestic wells from contamination by water 
that is polluted in its course past dwellings. The use of fertilizers 
must also be considered a possible source of pollution, because the 
ground water in these valleys is so definitely restricted. 

WELLS. 

Wells hetween Oceanside and Delmar. — Well F 5 is on the edge of 
the tidal marsh about 2 miles from the mouth of Buena Vista Creek, 



170 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

about 20 feet above sea level. It is a dug well, 13.9 feet deep, in 
which on October 25, 1914, the water level stood 10.1 feet below 
the surface of the ground. Water is lifted by a windmill to an 
elevated tank having a capacity of about 1,000 gallons. The water 
is used for domestic supply and to a small extent for irrigating a 
small vegetable garden. This well is on the flood plain of Buena 
Vista Creek at the mouth of a small tributary canyon which heads 
near the summit of Mount Kelly. A few rods east of the well there 
is a sharp bend in the creek valley, and the body of valley fill is 
locally constricted. The water in the well is derived from the shallow 
fill in the canyon which receives both seepage and underground 
drainage from the adjacent mesa. 

Well F 8 is 2J miles northeast of Encinitas, in the bottom of the 
canyon of a small intermittent stream tributary to Batiquitos 
Lagoon. The surface of the well is about 65 feet above sea level 
and about 350 feet below the surface of the mesa in which the steep- 
walled canyon is cut. This is a dug well 17 feet deep and 2.5 feet 
square. On October 25, 1914, the water level was 12 feet below 
the surface. The well is at the roadside some distance from any 
dwelling and is apparently little used. Water is lifted by means 
of a rope and bucket. The water is derived from the shallow fill 
in the canyon, which receives both the surface and underground 
drainage from the adjacent mesa. 

The Cardiff municipal water supply is obtained from wells (F 9) 12 
feet apart in a small valley just northeast of Encinitas. The following 
information was furnished by D. C. Ingersoll : Two wells, 8 inches in 
diameter, have been drilled to depths of 60 and 160 feet, respectively. 
Water was obtained at depths of 15, 30, 75, 125, and 160 feet, but 
in the shallower well the principal supply of water is obtained in fine 
sand between the depths of 30 and 60 feet and in the deeper well in 
sand between the depths of 140 and 160 feet. Both wells are cased 
to the bottom and are finished with screens. In the shallow well 
the water stands 20 feet and in the deep well 60 feet below the surface. 
The pumping plant consists of a gasoline engine and a lift pump, 
with cylinder 3 J inches in diameter and 16 inches long, used in the 
deeper well, and a windmill and lift pump with cylinder, 3J inches 
diameter and 14 inches long, in the shallower well. The maximum 
yield by pumping is, for the deeper well, 25 gallons a minute and for 
the shallower well 10 gallons a minute, the lower yield in this well 
being attributed to the fineness of the screen, which does not allow 
the water to enter rapidly enough. The water is used for domestic 
supply. The water from the shallow well is of good quality but 
somewhat hard ; that from the deeper well is very hard and slightly 
brackish and is therefore no longer used. 



WATER m THE MINOR VALLEYS. 171 

In 1914 a third well was being dug. If completed as planned, this 
well is 10 feet in diameter at the top and is reduced to 32 inches at the 
depth of 34 feet. The plans provided for a 32-inch steel casing to be 
sunk to a depth of 50 feet below the surface, the insertion of a 6-inch 
perforated point about which gravel was to be filled in, and the with- 
drawal of the large casing, leaving the point embedded in gravel to 
exclude sand from the well. It was estimated that this well would 
yield at least 50 gallons a minute, as the material between the depths 
of 28 and 60 feet apparently holds an abundant supply of water. 
The material penetrated by this well consists principally of fine sand 
interbedded with two or three layers of blue clay, each about 2 feet 
thick. 

Well G 15 is a stock well, on Encinitas Creek about 2 miles north 
of Olivenhain. It is 15.6 feet deep and the depth to water on October 
25, 1914, was 4.4 feet. Water is pumped by means of a windmill. 
There are no dwellings or other buildings in the immediate vicinity. 
The stream branches at this locality and forms a triangular area 
near the center of which the well was sunk. The bedrock in which 
the valley is cut is a white sandstone underlain by a green shale that 
outcrops north 6f Olivenhain. The valley contains a moderate 
depth of fill into which the drainage sinks. There is no doubt an 
adequate supply of water in this valley to supply a considerable num- 
ber of such wells if they were needed, but the water stands so near 
the surface that irrigation is hardly necessary on the few acres of till- 
able and irrigable land in this locality. 

Wells in McGonigle Canyon (K 3 to 9, inclusive). — The wells in 
McGonigle Canyon range in depth from 9 to 40 feet. Two of these 
are drilled wells, one 18 and the other 40 feet deep, both cased 
with cement tiles. The depth to water in the wells of this valley 
ranges from 7 to 37 feet below the surface, and each well yields a 
supply adequate for domestic use. Mr. John Stilling's well (K 4) 
is on the side of the valley and penetrates green shale. Definite 
information in regard to the well log was not available, but it is 
probable that the water enters the well above the shale bed. The 
other wells derive their supplies from the shallow alluvium in the 
canyon. The valleys tributary to McGonigle Canyon near its head 
carry the drainage from the west slopes of Black Mountain. From 
the foot of Black Mountain to the coast the canyon cuts through 
sandstones containing a few comparatively thin beds of shale. The 
valley fill probably does not exceed 25 feet in thickness anywhere 
in this canyon and in most places is much less. Though the supply 
of ground water in this canyon is not large, it is no doubt ample 
for domestic use. Information concerning the quality of the water 
from wells K 3 and K 8 is given in the table on page 260. 

Wells between Los Penasquitos Canyon and Mission Valley. — Well K 
11 is a dug well, 13.6 feet deep, the water level being 8.9 feet below 



172 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

the surface. It is on Los Penasquitos Creek about a mile below 
Poway Valley. It is pumped by a windmill that delivers water to a 
tank 400 feet west of the well. The valley fill at this place is partly 
coarse granitic alluvium and partly sand and gravel. The north slope 
of the valley is formed by granite thinly covered by alluvium and soil, 
but the south wall is formed by gravel. All the drainage from Poway 
Valley passes this locality, and conditions appear to be particularly 
favorable for procuring water from shallow wells. There are no wells 
below this place in Los Penasquitos Canyon, but sufficient water for 
domestic use could be obtained by sinking wells almost anywhere on 
the canyon floor. A body of basaltic rock crops out in the center 
of sec. 27, T. 14 S., R. 3 W., through which the creek has cut a short, 
narrow gorge. This rock forms an underground dam that brings 
the ground water to the surface and produces a surface stream in 
the little gorge. On October 24, 1914, an estimated flow of about 
half a second-foot was passing through the gorge. The canyon floor 
just above the gorge should be a particularly favorable site for shallow 
wells. Los Penasquitos ranch, of which Mr. Charles Brown is pro- 
prietor, includes practically the entire valley o£ Los Penasquitos 
Creek. The ranch house is supplied with water from a spring (K 10), 
near the house and the stock is watered from the stream. A small 
irrigation system is supplied with water from a reservoir at the mouth 
of a small intermittent stream in the west-central part of sec. 24, T. 
14 S., R. 3 W. 

Wells in Soledad Canyon. — A tidal marsh extends into the lower part 
of Soledad Canyon. Well K 18, which is 1 mile above Sorento or 3 
miles above the marsh, yields water which, although used for domestic 
supply, is said to be saline and of very poor quality. This well is 
12.4 feet deep and 3 feet square, and its water level is 9.5 feet below 
the surface. On October 24, 1914, water was standing in pools on the 
surface at several places within 200 feet of this well and appeared 
to be at very shallow depths everywhere on the valley floor as far 
east as the mouth of Carroll Canyon. 

Well K 19 is about 1 mile above K 18, on the south side of the 
canyon. The owner, W. T. Melbourne, stated that it yields an ample 
supply for domestic use but not sufficient for irrigation. It was 
originally 12 feet deep but has silted up somewhat and in October 24 
was found to be only 8.9 feet deep, with a water level only 3.6 feet 
below the surface. Water is pumped by means of a windmill and a 
suction pump, with 3-inch cylinder and 8-inch stroke, to an elevated 
tank having a capacity of 1,000 gallons. The yield of the well was 
not ascertained but Mr. Melbourne stated that with the windmill 
running at a rapid rate the water level was lowered about 2 feet in 
two or three hours. The well has never been dry and the water level 



WATER IN THE MINOR VALLEYS. 173 

fluctuates only slightly. A short gully in the canyon wall debouches 
on the canyon floor just south of the well and the stream channel from 
the mouth of the gully swings to the west and joins the main channel 
a short distance below the well. A hole 2 feet deep and about 10 feet 
square in this channel contained several inches of water when it was 
visited and Mr. Melbourne stated that he had never known it to be 
entirely dry. Water is pumped from this hole to irrigate 4 acres of 
alfalfa and 4 acres of apricots. The pumping plant consists of a 
6-horsepower gasoline engine and a small centrifugal pump. It can 
be run about 15 minutes before the hole is pumped dry. 

Well K 20, owned by Mr. Max Dietrich, is about a mile east of well 
K 19, near the mouth of Carroll Canyon, which is tributary to Soledad 
Canyon. It is a dug well, 9 feet in diameter and 20 feet deep, and its 
water level is 4.5 feet below the surface. It is pumped by a windmill 
and supplies water for domestic use. 

Soledad and Carroll canyons are very narrow, as is shown on Plate 
II, and their floors lie 100 to 400 feet below the level of the mesa 
through which they are cut. Gravels, shales, and sandstones outcrop 
in the canyon walls, the gravels being at the top. The valley fill 
east of Sorrento is probably 30 or 40 feet deep but it gradually dimin- 
ishes in depth toward the east until in the upper parts of Soledad 
and Carroll canyons the bedrocks appear at the surface on the canyon 
floors. The streams that occupy these canyons are intermittent, 
but even during dry seasons considerable water from the adjacent 
formations accumulates in the valley fill and percolates down the 
canyons, constituting an important source of domestic water supply. 

Wells in San Clemente County. — San Clemente Canyon, like Soledad 
and Carroll canyons, is very narrow and deep but contains a shallow 
deposit of valley fill into which water seeps from the gravels, shales, 
and sandstones that form the canyon walls, thus maintaining a ground- 
water supply during the long periods in which no surface water passes 
down the canyon. This canyon joins Rose Canyon at the foot of 
Soledad Mountain. 

On the canyon floor 2J miles from Rose Canyon is a shallow dug 
well (K 23) formerly used for stock but apparently abandoned at 
the time it was visited in 1914. No measurements of this well were 
obtained, but the water stood at the surface of the ground. There 
were also several shallow pools of water in the streamway in the 
vicinity of the well, indicating that shallow water is general. The 
surface is not marshy, as it is in the lower part of Soledad Canyon, but 
trees and grasses grow rank and show no evidence of drought. 

Well K 24, 2\ miles east of K 23, is a dug well 9.9 feet deep, in which 
the water level, on October 24, 1914, stood 4.5 feet below the surface. 
Water is pumped by a windmill to a stock trough. There are no 
dwellings within several miles. The canyon walls near this well are 



174 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

composed entirely of gravel, the top of which is cemented into a hard 
layer; but three-eighths of a mile west of the well these gravels are 
underlain by at least 12 feet of clay. 

Well K 25, owned by Mr. W. D. Bryson, is 2| miles northeast of 
K 24 and 1J miles south of Miramar. It is dug 6.7 feet deep and 2 \ 
feet square, and when visited its water level was 4 feet below the 
surface. The well was dry during the summer of 1913 but furnished 
sufficient water for domestic use and for a few head of stock during 
all of 1914. The water is pumped by means of a windmill to a tank 
at the house. The well is in the dry creek bed 460 feet above sea 
level and 40 feet below the level of the ground at the house. The 
water tank at the house is 10 feet above the ground. There is very 
little fill in the valley at this place and the quantity of water available 
is very small. Well K 26, a little less than half a mile east of K 25, is 
a small spring which is said to have been dry only three times in the 
last 23 years, the last occasion being in 1911. There was no flow at 
the surface when this spring was visited but water stood in a little 
pool and there may have been some underflow. 

Wells south of Mission Valley. — Well O 9 is in Spring Valley, about 
3 miles southeast of Lemon Grove. It is 24 feet deep, 8 feet in 
diameter, and, on Octobei 5, 1914, the water stood 10 feet below the 
surface. It is pumped by a windmill and supplies a stock trough but 
the water is regarded as too brackish for any other use. 

All the shallow water in the middle and lower parts of Spring 
Valley is said to be brackish and no deep wells have been sunk. The 
upper part of the valley is .cut in crystalline rocks, but the middle 
part, down to about a mile from the mouth, is cut in Tertiary sedi- 
mentary rocks. The water, therefore, is obtained in part from areas 
underlain by crystalline rocks and in part from surface drainage from 
areas underlain by the sedimentary rocks and by seepage from these 
rocks. 

MINOR VALLEYS IN THE HIGHLAND AREA. 

Topography. — Along the stream channels throughout the highland 
area are numerous small valleys, formed where widening of canyon 
bottoms for short distances have afforded opportunity for the depo- 
sition of alluvial material. Many of these valleys are only a few acres 
in extent; others comprise 20 to 50 acres. Most of them are at ele- 
vations higher than those of the highland valleys traversed by the 
major streams. 

The floors of these valleys consist largely of valley fill which in 
many places merges imperceptibly into the residuum of the sur- 
rounding hill slopes. The drainage system of one of the more impor- 
tant minor valleys is made up of several streams that drain the sur- 
rounding slopes and meet in the valley to form a single stream leading 
to the drainage outlet. 



WATER IN TERTIARY AND OLDER FORMATIONS. 175 

Materials of the valley fill—The rocks surrounding all highland 
valleys are practically impervious. In the larger valleys alluvial 
material accumulates along the stream channels, in many places 
merging gradually into the residuum which, as a rule, is present over 
all but the steepest parts of the highland areas. The depth of the fill 
at the lower ends of minor valleys that are tributary to major valleys 
equals that of the adjacent fill of the larger valleys, but decreases 
upstream at a rate depending on the steepness of the ancient canyon. 
Thus, at the mouth of Guejito Creek, in San Pasqual Valley, the fill is 
at least 150 feet deep (well H 30), but bedrock appears in the canyon 
bottom not more than 1£ miles up this creek. In Moosa Canyon the 
fill is about 60 feet deep at the lower end and the bedrock appears in 
the valley bottom about 4 miles upstream. As a rule also, the alluvial 
material near the main valley is very fine and yields little water. This is 
illustrated by well H 30 in a branch of San Pasqual Valley, which pene- 
trated 150 feet of sand and silt with a 12-inch casing, and when tested 
is reported to have yielded only 90 gallons a minute, in marked con- 
trast with the large yields from wells in the main valley near by. The 
fill of a typical highland valley, however, consists largely of medium 
and coarse sand with occasional layers of fine gravel. It contains 
ground water in its pore spaces and in every respect constitutes a 
small ground-water reservoir, but the depth of the fill seldom exceeds 
50 feet and in the smaller valleys is much less. 

Water table— The water table in a minor highland valley behaves 
much like that in a minor valley of the coastal belt, but as a rule it is 
aearer the surface and its slope downstream is less. Its annual 
fluctuations and its fluctuations from year to year are probably also 
'ess, owing to the longer period of stream flow and the greater prob- 
ability of run-off in dry years. 

Ground-water yield.— The quantity of ground water obtainable 
n these valleys varies with the dimensions of the fill and the perma- 
lence of stream flow. 

The types of wells to be used and the method of selecting well 
dtes are the same as in the minor valleys of the coastal belt. (See 
' 169.) 

SVATER IN TERTIARY AND OLDER SEDIMENTARY FOR- 

MATIONS. 

By A. J. Ellis and C. H. Lee. 

WATER-BEARING CAPACITY OF THE FORMATIONS. 

Tertiary and older sedimentary formations underlie the southern 
•art of the San Onofre Hill district, between the northern boundary 
f San Diego County and Santa Margarita River, and the Linda 

ista terrace district, and include also the relatively small Tertiary 



176 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

stream deposits that occur at irregular intervals on the hills between 
Miramar and Witch Creek. (See PI. III.) 

The Tertiary rocks consist of conglomerate, sandstone, sandy shale 
clay, and limestone. (See p. 52.) From Los Penasquitos Canyon 
southward thick beds of conglomerate, which constitute the upper 
part of the San Diego formation, lie at or near the surface wherever 
the elevation exceeds 200 feet above sea level, and these beds are 
underlain by and in some places interbedded with alternating lentic- 
ular layers of sandstone, sandy shale and clay, all of which are small 
From Los Penasquitos northward to Buena Vista Creek the surface 
formation is a porous sandstone that is underlain by alternating 
layers of shale, sandstone, and limestone that are ordinarily continu- 
ous over wide areas. North of Buena Vista Creek the rocks are 
similar to those in the southern part of the area. 

The conglomerates are composed of rounded pebbles and smal 
boulders, most of which are less than 4 inches in diameter, cementec 
together by hard calcareous clay. Where these conglomerates lie 
at the surface they are, as a rule, covered by a thin soil of sandy or 
gravelly clay. This formation differs from most coarse deposits in 
being nearly impervious and incapable of absorbing much water 
The clay soil, by resisting the descent of water into the ground, serves 
as an additional obstacle to the absorption of water. 

The shales also are practically impervious and usually yield water 
at a rate too slow to afford satisfactory supplies to wells. 

The most favorable sources of water in the Tertiary rocks are the 
layers of sand. Their porosity is high, and the water circulates in 
them freely enough to supply wells wherever they are saturated. 
But a condition most unfavorable to the storage of water, even in 
the most porous of the strata, is the deep dissection of the region, 
which favors rapid drainage of all the beds that lie above the levels of 
the canyon floors. As all the principal streams have cut their valleys 
practically to sea level, the deposits that lie above the levels of the 
valley floors are completely drained during the annual periods of 
drought that characterize the climate of this region. Generally 
speaking, therefore, available water does not occur in the Tertiary 
rocks at elevations exceeding 100 feet above sea level in interstream : 
areas, and in areas adjacent to the valley walls it is probably not 
above the level of the canyon floors. 

SAN ONOFRE HILL DISTRICT. 

In the San Onofre Hill district, north of Santa Margarita River, 
the rock formations consist of breccia, coarse gravels, and layers of 
sandstone and shale. They are thoroughly and deeply dissected, 
so that there is very little tillable land between the streams. All 
these lands are included within the Santa Margarita y Las Flores 



WATER IN TERTIARY AND OLDER FORMATIONS. 177 

land grant, which has not been subdivided or opened to settlement, 
and, so far as known, no attempts have been made to obtain supplies 
of ground water except near the mouth of Arroyo San Mateo. On 
account of the thorough dissection of interstream areas, the forma- 
tions, especially the slightly indurated conglomerates, are probably 
quite thoroughly drained above the stream levels. It is possible, 
however, that drilling will disclose conditions more favorable for the 
storage of ground water than are now known. In general, the breccia 
of the district is, with respect to the occurrence of ground water, 
probably comparable to other crystalline rocks (see p. 189); the 
surrounding formations probably contain water below levels corre- 
sponding approximately to the levels of the streams. 

TERTIARY GRAVEL TRACTS. 

The stream gravels that occur in discontinuous patches from Mira- 
mar to Witch Creek stand in high ridges capping crystalline rock hills 
and are in general very thoroughly dissected. At present there is 
practically no settlement in areas underlain by these deposits, and, 
so far as known, no attempts have been made to obtain from them 
supplies of ground water. Because of the ease with which they may 
be drained, they probably do not, as a rule, contain permanent sup- 
plies of ground water; it is possible, however, that in some places 
wells drilled to bedrock would obtain lasting supplies. The well 
(K 23; see log, p. 68) drilled for oil on the Poway terrace is said to 
have encountered at a depth of 525 feet a very strongly mineralized 
water that rose 100 feet in the casing. Failing to obtain oil, the well 
was abandoned. It was remote from any settlement, and no attempt 
was made to use the water, which was, however, said to be unfit for 
drinking. 

LINDA VISTA TERRACE DISTRICT. 
GENERAL CONDITIONS. 

As described on pages 52-67, the coastal belt south of Santa Mar- 
garita River is underlain mainly by Tertiary formations comprising 
rocks of Eocene age and by the Miocene and Pliocene strata that are 
designated in this report the San Diego formation. As shown on 
the geologic map (PI. Ill), the Eocene deposits appear at the surface 
from Los Penasquitos Canyon northward to Buena Vista Creek; the 
San Diego formation is exposed at the surface from Buena Vista 
Creek northwestward and from Los Penasquitos Creek southward; 
but where the San Diego formation is exposed at the surface it is 
generally underlain by Eocene strata." In the major valleys the 
Tertiary bedrocks are overlain by alluvium, as shown on Plate III, 
and although the alluvium is the principal source of ground water, 
115536°— 19— wsp 446 12 



178 

some wells pass through it and draw their supplies from underlying 
Tertiary beds.' 

Most of the area between Los Penasquitos Canyon and Mission 
Valley, locally called Linda Vista Mesa, is uncultivated and unset- 
tled and is covered only by sparse native vegetation. Several of 
the attempts that have been made to procure supplies of ground 
water have failed because of difficulties encountered in drilling through 
conglomerates and inability to reach water within a few hundred 
feet of the surface. So far as known, however, none of the wells 
reached within 100 feet of sea level, at which depth water might 
have been obtained. 

In the western part of the coastal belt, between Mission Valley and 
Otay Valley, the upper part of the San Diego formation, including 
much of the conglomerate, has been removed by the cutting of 
marine terraces. A number of wells sunk in this area have obtained 
water at depths within about 100 feet of sea level. Conditions most 
favorable for the occurrence of ground water were found on terraces 
less than 200 feet above sea level, including Chula Vista and Nestor 
terraces. (See p. 26.) 

South of Otay Valley the principal terrace, which corresponds to 
Linda Vista Mesa, has been raised to an elevation about 500 feet 
above sea level. This terrace is Otay Mesa. Here a few drilled wells 
furnish meager quantities of water, as described on page 179. 

WELLS ON THE HIGH TERRACES. 

K 1. — John Haflie's well is about 5 miles northeast of Delmar, at 
the top of the bluffs along the east side of San Dieguito Valley, 275 
feet above sea level. The well is 6 inches in diameter and 200 feet 
deep, and although definite information was not obtained it is 
probably largely in granite, as this rock outcrops only a short distance 
from the well. This well does not, therefore, represent supplies avail- 
able in the sedimentary rocks. Water is lifted by means of a wind- 
mill and not more than 150 gallons per day is pumped. 

K 21. — A well drilled about 1 mile northeast of Miramar reached 
the depth of 300 feet, finding no trace of water. It penetrated 
loose red clay and gravel and ended in a light-colored shale. The 
casing was withdrawn and the well abandoned. 

K 29. — A well belonging to Mr. Rodger Topp, on Linda Vista Mesa, 
about 4 miles north of Mission Valley and 2 miles northwest of Rose- 
dale, at an elevation of 400 feet, penetrated conglomerate to the 
depth of 260 feet without reaching water and ended in a white sand- 
stone, which is probably the Eocene rock that crops out in Los Penas- 
quitos Canyon. (See p. 53.) A rotary drill 12 inches in diameter, 
which was used, was unable to penetrate a hard layer encountered at 
the depth of 260 feet. 






WATER IN TERTIARY AND OLDER FORMATIONS. 179 

8. — The community well drilled at Angelus Heights for the San 
Diego Homebuilders' Association is 375 feet deep, 10 inches in diameter, 
and cased throughout with standard casing. The elevation of the 
well is said to be about 400 feet and potable water was reached at the 
depth of 215 feet. Water-bearing sand was reached at 370 feet, but 
the water was salty and had to be cut off. The present supply, 
about 36 gallons a minute, is obtained from the 2-foot layer of sand 
and gravel at the depth of 215 feet. 

P 8, P 9, P 10. — Three wells drilled on Otay Mesa, at elevations of 
about 500 feet, produced water suitable for domestic use. According 
to Mr. Wilkes James, who furnished the information, one of the wells 
(P 8) was being drilled at Loma Alta school, at the middle of the south 
line of sec. 27, T. 18 E., R. 1 W., and on November 10, 1914, had 
reached a depth of about 700 feet, obtaining a small quantity of 
water. Mr. RouTs well (P 9), drilled in the SW. i sec. 35, T. 18 S., 
R. 1 W., is 310 feet deep and yields about 12 gallons a minute of 
water of good quality for domestic and stock use. Mr. Willpot's well, 
in the northeast corner of sec. 2, T. 19 S., R. 1 W., is 280 feet deep and 
yields a few hundred gallons of water a day, the water being of 
good quality for domestic use. 

1. — A well, 8 inches in diameter, owned by the San Diego Young 
Men's Christian Association, was drilled at the corner of Eighth and 
C streets, San Diego, to the depth of 200 feet. Salt water was en- 
countered at the depths of 85 feet and 100 feet, but was cased out, 
and fresh water was struck 140 feet below the surface in a 5-foot 
bed of sand that yielded 45 gallons a minute. It is said to be unsatis- 
factory in quality, however, because it discolored the tile lining of a 
swimming tank that the well was intended to supply. 

la. — Mr. Wilkes James's well, 2 miles east of San Diego, is about 
160 feet above sea level. It was drilled 8 inches in diameter and 248 
feet deep. Water was reached at the depth of 129 feet, but only a 
small quantity was obtainable between this depth and the depth of 
190 feet. At 190 feet the drill penetrated a bed of coarse sand and 
gravel that yielded water freely. On November 19, 1915, the water 
level stood about 118 feet below the surface. No pump had been 
installed. 

3. — The well of B. G. Estes, situated about 3 miles east of San 
Diego at an elevation of 175 feet above sea level, was dug to the depth 
of 155 feet. A perforated casing, 6 inches in diameter, is driven in 
the bottom to a total depth of 178 feet. Water encountered in small 
quantity in a bed of sand between the depths of 145 and 155 feet rose 
4 feet above the top of the sand. The driven point penetrated a 
3-foot layer of hardpan about 168 feet below the surface, under which 
it entered a water-bearing sand from which water rose 2J feet above 
the bottom of the dug part of the well, or to a level 155J feet below 



180 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

the surface of the ground. The pumping plant consists of a deep- 
well pump and a distillate engine, which are operated at a cost of 6 
cents per 1,000 gallons of water pumped. About 35 acres of orchard, 
chiefly lemons, are irrigated. 

14. A well owned by Mr. L. Wiese was dug to the depth of 76 
feet and drilled from that depth to 104 feet. The material penetrated 
consists of alternating layers of blue and gray clay with a few beds of 
gravel. On October 8, 1914, the water stood 62 feet below the 
surface. The yield is too small to afford water for irrigation but an 
ample supply of water for domestic use is obtained. The cost of 
this well was $1 per foot for digging and $3 per foot for drilling, making 
a total of $160. The pumping plant consists of a windmill and a 
suction pump. 

7. A well owned by Robert Dick, about 5 miles east of San 
Diego on the south side of Las Chouas Valley and about 250 feet above 
sea level, is 10 inches in diameter and 203 feet deep and affords a 
satisfactory domestic supply of water which was struck at a depth of 
114 feet. (See log, p. 62.) 

DEEP WELLS ENDING IN SEDIMENTARY ROCKS UNDER VALLEY FILL. 

F 7. A well was drilled for oil by the Pacific Laguna Oil Co., on the 
valley floor of Batiquitos Lagoon, 4 miles north of Encinitas, at an 
elevation of about 20 feet above sea level. No detailed information 
could be obtained in regard to the log of this well. The well is said 
to be about 1,300 feet deep and to end in " black sand which was 
overlain by red rock." It was reported that at a depth of about 
800 feet a water-bearing bed was penetrated from which water rose 
to the surface. When the well was visited, November 25, 1914, it 
was flowing about 5 gallons a minute over the top of the casing, which 
stood about 1 foot above the ground level. This well apparently 
has been abandoned. 

K 16. The first McNeese oil boring, which was abandoned because 
it became crooked at a depth of 1,700 feet, is in Soledad Canyon, at 
Sorrento, at an elevation of about 35 feet above sea level. Water 
that flows at the surface was reached at a depth of about 600 feet. 
This water is said to be warm, but neither the temperature nor the 
flow could be determined when the well was examined, because the 
exhaust from the engine which is working on the new hole discharges 
into the well. The new hole is less than 200 feet from the old one 
and was 1,000 feet deep when it was visited September 22, 1914, 
but no information could be obtained in regard to water encountered. 

K 30. When K 29 failed to reach water, a second well was 
drilled in Murphy Canyon just east of Rosedale, at an elevation 
of about 150 feet above sea level. This well is 618 feet deep 
and 10 inches in diameter. Water was reached first in a thin 



WATEE IN TERTIARY AND OLDER FORMATIONS. 181 

layer of sand at the depth of 125 feet, and at the depth of 250 
feet a bed yielding warm sulphur water was encountered. The water 
stood about 15 feet below the surface of the ground October 10, 1914. 
Water is reported to have been pumped at the rate of 270 gallons a 
minute without apparent effect on the yield. It was said that the 
water is to be used for domestic supplies in Rosedale, which is 425 
feet above sea level or 275 feet above the well site. 

K 37. The Balboa oil boring (see log, p. 55), encountered artesian 
water at the depth of 900 feet. On August 31, 1912, the measured 
flow was 45 gallons a minute. This water was warm and had a 
brackish taste. Other water-bearing beds were reached at depths of 
2,300, 4,152, and 4,217 feet, respectively, but little is known con- 
cerning these beds. As neither the quality nor the quantity of the 
flowing water changed greatly after drilling below 1,000 feet, it is 
believed that none of the lower formations yield artesian water. 
According to the well log published by Merrill (p. 56), an artesian 
flow was obtained at the depth of 335 feet, and other water-bearing 
beds were penetrated at depths of 510 feet and 725 feet. 

K 53. The well belonging to Mr. J. L. Haughawout is in Alvarado 
Canyon, about 1J- miles northwest of La Mesa. It is a dug well 74 
feet deep, all in Tertiary conglomerate. In the upper 70 feet the 
interstices between the gravels are filled with clay, but in the lower 
4 feet the spaces are filled with sand. The water usually stands about 
25 feet below the surface, but in wet seasons it sometimes rises within 
2 feet of the top of the well. The average yield is about 2 gallons a 
minute and the well has been pumped dry by drawing water at the 
rate of 1 8 gallons a minute. The well is not used except in dry seasons 
when other sources of water fail. 

NESTOR AND CHULA VISTA TERRACES. 
SOURCES OF WATER. 

The Nestor and Chula Vista terraces are underlain by deposits 
belonging to the middle part of the San Diego formation (see 
pp. 58-67), which in some places is overlain by a thin mantle of 
Pleistocene, as shown on Plate II. As a rule, this part of the San 
Diego formation contains no conglomerates; the beds consist of 
sandy clay, sand, and gravel, all in more or less lenticular and irregu- 
lar layers, as shown in Plates XXVI and XXVII, wells numbered 
O 133, O 124, O 121, and O 122. 

A study of fluctuations of ground water and the general shape and 
position of the water table was made in the region between Tia 
Juana and Sweetwater valleys, which is less than 100 feet above sea 
level (PI. XX). The elevation of the water table from September, 
1914, to August, 1915, was observed in 30 wells in this area, 



182 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

and records were kept at 25 wells in the three adjacent river valleys. 
The positions of these wells are shown on Plate XX, and other infor- 
mation in regard to them is given in Table 45 (p. 209) . A summary 
of observations, with dates and elevations of maximum and minimum 
water levels is given in Table 30 (p. 126). The depth to the water 
table ranges from about 10 feet on a low terrace in Tia Juana Valley 
to 20 feet or more on the terrace near Nestor, 40 feet or more at 
Chula Vista and Otay, and 100 feet or more beneath the higher 
terraces. The maximum,, minimum, and average annual range of 
fluctuations in wells under observation is shown in Table 32 (p. 133). 
The observations indicate an annual range of 0.17 to 8.76 feet, with 
an average of 2.76 feet, although this average is not representative 
of the formation as a whole. The type of fluctuation is shown in 
Plate XLV, and, with the exception of wells near Otay River, is 
remarkable for the late date — about May 1 — at which the highest 
ground-water level occurs and also for the slight range of fluctuation. 

Ground-water contours at the approximate dates of lowest and 
highest ground-water level in the adjacent river valleys are shown on 
Plate XX. Ground-water profiles along lines A-A, B-B, C-C, and 
D-D (PL XX) are shown in Plates XXXIV, XXXV, XLIV, and 
XLVI, respectively. The ground-water contours and profiles show 
a general slope of the water table from the hills toward the bay and 
ocean, but that this slope is not so steep as that in the river valleys. 
It shows also that in the period of lowest ground-water level in the 
river valley the water table beneath the mesa lands is little if any 
lower than that in the river valleys, but in the period of highest 
level in the river valleys it is considerably lower, and that a steep 
ground-water slope then exists from the river valleys into the adj acent 
mesa areas. 

The ground-water in these low mesa areas is derived by percola- 
tion (1) directly from rainfall, (2) from small canyons debouching 
onto the slopes from the higher mesa areas to the east, (3) from irri- 
gated areas, (4) laterally from adjacent river valleys, and possibly 
by underground drainage from the higher terraces on the east. The 
percolation of water from valley fill into the Tertiary beds is believed 
to account for the fact that the rise in ground-water during the period 
of replenishment was greatest adjacent to the river valleys, and that 
between Sweetwater and Otay valleys there was little or no rise 
except opposite the mouth of Telegraph Canyon, where the rise was 
far less than that taking place near the river valleys (PI. XX) . The 
greatest rise in ground-water was observed in wells on the mesa imme- 
diately north of Tia Juana Valley, and percolation from that valley 
may be the most active single source of supply of ground-water. 
The time elapsing between the first flood in Tia Juana Valley, January 
29, 1915, and the maximum height of the ground-water level in six 



WATER IN TERTIARY AND OLDER FORMATIONS. 183 

wells within a mile north of the edge of the valley indicates an average 
daily advance of the crest of the ground-water wave of 20 feet. The 
height of the crest at the edge of the valley was 6 to 8 feet. The 
height of the crest at a distance of a mile was about a foot. At Otay 
and Sweetwater valleys, where the rise of ground-water was only 
4 feet, the effect was barely noticeable at a distance of a mile. In 
ordinary years, when there is little or no stream flow in these two 
valleys, the distance would be even less. Percolation from river 
valleys as a source of supply for this formation is thus very small at 
distances of a mile or more. 

YIELD OF WELLS. 

Conditions affecting yield. — The quantity of water obtainable from 
the San Diego formation underlying the Nestor and Chula Vista 
terraces between Sweetwater and Tia Juana rivers by pumping from 
wells depends chiefly on the distance of the wells from the nearest 
major river valley. Even at a distance of several miles from a river 
wells in this formation should yield sufficient water for farm, domestic, 
and stock use and the irrigation of small gardens. In order to sup- 
plement a deficient gravity supply in very dry years, in districts such 
as those about National City and Chula Vista, successful wells may 
yield sufficient water to irrigate small orchards if used in connection 
with a small tank or reservoir. As a rule, however, a well more than 
a mile from a river valley will yield only a small supply, and pro- 
tracted pumping from many wells in the same vicinity will seriously 
lower the water level. 

Successful wells in the San Diego formation within a mile north of 
Tia Juana Valley will yield sufficient water in average and wet years 
to irrigate alfalfa and garden truck, but the cost of installation and 
expense of pumping are greater than in the Tia Juana Valley, from 
which this area probably receives its supply of water. Where good 
water-bearing gravels are within reach, a single plant of one or two 
wells will furnish sufficient water, as indicated by the test of well 
O 47 (p. 270) ; where the water-bearing strata consist of sandy or 
gravelly clay, several wells may be necessary (see wells O 110, O 116, 
and O 111). From the rise of the zone of saturation (PL XX) it 
is estimated that in 1915, between January 6 and May 1, approxi- 
mately 700 acre-feet of water was absorbed, a quantity probably in ex- 
cess of that usually absorbed, as the flood flow of Tia Juana River was 
exceptionally large and prolonged and water was carried by an overflow 
channel that crosses the low terrace lying at the general level of the 
valley floor south of Nestor. In dry years the yield of wells in this 
area would probably not be sufficient for the irrigation of alfalfa, 
particularly if the cultivation of a large proportion of the land is 
attempted; it should be ample, however, for domestic use and for 
the irrigation of small tracts in vegetables or trees. 



184 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Conditions that affect the rate of yield of wells in the San Diego 
formation are in general the same as those that have been fully dis- 
cussed for wells in the fill of the major valleys (p. 155). 

Interference of wells. — The yield of wells on these low terraces occa- 
sionally shows strongly the effect of pumping at one well on the water 
level and yield of other wells drawing from the same water-bearing 
stratum. This effect is noticeable in wells in valley fill that are 
spaced at intervals of less than 1,000 feet but not at greater distances 
unless the pumps are of large capacity and the pumping is long 
continued. However, within a lens of gravel or sand surrounded by 
relatively tight materials this effect may appear instantly at distances 
exceeding 1,000 feet; it is not due to a lowering of the zone of satura- 
tion within the area of influence but to a decrease of hydraulic 
pressure within the gravel lens. The degree of lowering in each well 
varies with the facility with which changes in pressure are transmitted 
through the ground water. If there is sand or clay in the voids of 
the gravel, changes in pressure are not transmitted as far as if the 
voids are open. 

A striking illustration of well interference of this kind was observed 
in Otay Valley, directly north of Palm City, at wells O 92, O 38, 
O 35a, and O 90 (PI. XX) ; the first three are 12-inch cased wells and 
the last is a shallow dug well. The casing of well O 92 is in a pit dug 
below the water table but sealed off from the gravel stratum pene- 
trated by the casing. Inspection of Plate XXVII shows that wells 
O 35a and O 38 penetrate and end in a porous stratum below clay 
at a depth of about 100 feet. The drillers reported that both wells 
draw from the bottom only. The log of well O 92 could not be ob- 
tained accurately, but the well is reported by the driller to be 198 
feet deep and to penetrate alternate layers of clay and gravel to a 
considerable depth. It is to be noted that the fill of Otay Valley at 
this point is less than 30 feet deep and is underlain by the San Diego 
formation. Well O 92 is about 1 ,200 feet from well O 35a, and well O 38 
is 1,100 feet from well O 35a. Well O 90 is 200 feet from well O 35a. 
Well O 92 was equipped with a 4-inch horizontal centrifugal pump, 
probably raising from 400 to 450 gallons a minute, which was used 
to lift water to the top of a tower for the purpose of washing gravel. 
It was in operation about eight hours daily except Sunday or when 
the plant was for any reason temporarily shut down. Well O 38 
was equipped with a 3-inch horizontal centrifugal pump with a 
capacity of not over 225 gallons a minute. The water was used to 
irrigate 10 acres of alfalfa and the pump was operated at intervals as 
needed during the irrigation season. Well 35a was equipped with 
a 24-inch centrifugal pump with a capacity of not more than 150 
gallons a minute. The water was used for domestic supply and to 
irrigate a small garden, the pump being operated for a few hours, at 



July 



/>&5r-~- 



July 



I IN 4 

EGO 










WATJ 


R-SUPFLY PAPER lie, PLATE XLV 




1914 


/SAS 








Apr. 


May 


June 


July 




WELL K 34 ! JC 
u/bn M/,y/5epft-/y.eFS3nl>iego fr 














- L 


-0 * 






















L_ 







NOTE: Dotted lines connecting observations indicate 
approximate fluctuations during periods for which 
record is insufficient to show detail. 



DIAGRAM SHOWING FLUCTUATIONS OF MATER TABLE IN OBSERVATION WELLS 
IN SAN DIEGO FORMATION IN VICINITY OF SAN DIEGO BAY 1914-1915 



WATER IN TERTIARY AND OLDER FORMATIONS. 185 

intervals of two or three days, to fill a tank. Observations of water 
level (PI. XLV) in well O 90 and in the pit at well O 38 show the 
normal and regular type of fluctuation for dug wells in shallow valley 
fill; at well O 35a and in the casing at well O 38, however, fluctua- 
tions were very irregular and erratic. 

A study of pump operations in connection with these fluctuations 
shows that the operation of the pump at well O 92 causes much of the 
erratic fluctuation of wells O 35a and O 38, although pumping at well 
O 35a seems also to slightly affect well O 38, and probably the latter 
would be found to affect well O 35a, if observations had been obtained 
at the proper time. It is difficult from the available data to deter- 
mine the exact extent to which the pumping of one well lowers the 
water level in the others, but the lowering may be as much as 6 feet, 
judging by the marked recovery of water level at wells O 38 and 
O 35a April 30, when the pump at well O 92 was not operating, as 
compared with previous observations in March and April, when it was 
operating, and also the recovery observed December 6, when the 
pump was not operating as compared with November 6 preceding, 
when the pump was operating. That this lowering and subsequent 
recovery is not always instantaneous is shown by the fact that on 
October 9, 1914, a lowering of 0.72 foot occurred in the casing of well 
O 38 during the first ten minutes of operation of the pump after an 
hour's intermission at noon. It is also shown by the fact that on 
March 15, 1915, the water level rose 1.18 feet in 45 minutes that the 
pump was shut down. The full lowering or recovery probably 
requires several hours. 

The effect of interference was observed also in well O 39, about 500 
feet east of Otay, which penetrates the same gravel bed as well O 38. 
This well was sunk early in 1915, and beginning May 15, 1915, was 
pumped steadily from 5 to 10 hours a day at the rate of 60 gallons a 
minute. Observations at well O 39 (PI. XLV) indicate that a sudden 
drop of 5 feet in the water level in well O 39 occurred some time 
during May, and that this was not recovered during the remainder of 
the period of record, which ended August I. 

The probability of interference between proposed wells can not 
be determined except by actual test, owing to the irregularity of the 
gravel lens. The immediate result of such interference is to in- 
crease the cost of pumping to the extent of the increased lift; the 
ultimate effect would be to drain the gravel lens of its accumulated 
ground water more rapidly than if one well alone were drawing from 
it. In the examples described above, however, the local gravels 
appear to be readily recharged during the run-off season from the 
overlying valley fill and, except possibly in dry seasons, the supply 
would not become seriously depleted. 



186 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

WELL TESTS. 

Individual wells vary so widely in yield that it is impossible to make 
generalizations from which the yield of new wells can be predicted. 
Three wells on the low terraces between Otay and TiaJuana valleys — 
considered typical of the best wells of an area that probably affords 
more favorable conditions for well yield than any other area of Ter- 
tiary rocks in San Diego County — were tested. The tests were made 
as for wells in the valley fill and are described as follows : 

Well 115.— WeXl O 115, which is owned by W. E. Williams, is at 
the northern edge of Tia Juana Valley about 1J miles southeast of 
Nestor, in sec. 34, T. 18 S., R. 2 W. From the bottom of a dug pit 
5 feet square and 7.5 feet deep, curbed with redwood timbers, a drilled 
well, lined with 10-inch stovepipe casing, is sunk to a depth of 56 
feet. The principal water-bearing stratum of gravel is reached 53 
feet below the surface, is penetrated 3 feet, and yields water readily- 
(For log of well see PL XXVII.) Water probably enters at the bottom 
of the casing. The normal water level in the well ranges during the 
year from about 7.5 feet to 12 feet below the surface of the ground, as 
shown by measurements made during the season of 1914-15 (Table 
30, p. 126). At the time of the test the water stood 8.1 feet below the 
ground surface. During the test, which lasted 1 hour and 6 minutes, 
the well was pumped at the rate of 231 gallons a minute; the total 
drawdown, which was reached 36 minutes after pumping was started 
and remained constant to the end of the test, was 15.25 feet, so that 
the water level was 23.35 feet below the surface of the ground. The 
specific capacity of the well (see p. 158) was therefore a little more than 
15 gallons a minute for each foot of drawdown. As the dimensions 
of the perforated area were not obtained, the specific capacity of the 
gravels (p. 158) could not be computed. 

Well 47. — Well O 47, owned by Tucker & Evans, is 2 miles west 
of Nestor, in the SE. J sec. 29, T. 18 S., R. 2 W. It consists of a 
dug pit, 4 feet 8 inches by 8 feet 6 inches, and 19 feet deep, from the 
bottom of which a drilled hole, lined with 12-inch stovepipe casing, 
extends to a depth of 64 feet below the surface of the ground. The 
casing, which is not perforated, penetrates 14 feet into a good water- 
bearing stratum composed of gravel with few boulders, and the water 
enters at the bottom. (For log of well see PL XXVII.) In 
1914-15 the normal water level ranged from 21 feet to 32 feet below 
the surface of the ground (Table 30, p. 126). The well was pumped 
for 1 hour and 38 minutes at a rate of 373 gallons a minute; the 
resulting drawdown, which was reached 15 minutes after the pump 
was started, was 21 feet, or to 42 feet below the surface of the ground. 
The specific capacity of the well was therefore 18 gallons a minute 
per foot of drawdown. 



WATER IN" TERTIARY AND OLDER FORMATIONS. 187 

Well 102.— Well O 102, owned by R. J. Jaeger, is half a mile 
northeast of Nestor. It consists of a dug pit, 4 feet square and 110 
feet deep, at the bottom of which is drilled a hole. 20 feet deep, lined 
with 12-inch casing that projects 10 feet above the bottom of the 
pit; the total depth of the well is 130 feet. No very definite infor- 
mation could be obtained as to the log of the well, but the drilled 
section was said to be mostly in sand and, near the bottom, medium 
gravel. At the time of the test the normal water level measured 84 
feet below the surface of the ground. The well was pumped for 2 
hours and 6 minutes at the rate of 116.5 gallons a minute without 
lowering the water level. It is evident, therefore, that the well was 
not being pumped to its full capacity, the pump being too small to 
properly test the well, and the specific capacity could not be deter- 
mined. 

Discussion of well tests. — The results of well tests are summarized 
in Table 43 (p. 162). The tests of wells O 47 and O 115 indicate 
that in this area the specific capacity of wells penetrating open gravels 
is about 15 gallons per minute for each foot of drawdown. A single 
well penetrating open gravels should therefore yield about 300 gallons 
a minute for a 20-foot drawdown. Wells such as O 110, O 116, and 
O 111, which penetrate hardpan and adobe containing boulders and 
gravel, of which about 30 feet is saturated, would probably yield less 
than those reaching gravel. Experience with the best of such wells 
near the edge of Tia Juana Valley indicates that the specific capacity 
is about 10 gallons a minute per foot of drawdown. Where water is 
needed to irrigate alfalfa it is customary to drill several such wells 
in a group. The probable yield of a proposed well should be esti- 
mated, if possible, on that of wells in the immediate vicinity which 
are being pumped to capacity; if such information is not available 
the figures here given may serve as a rough guide. 

WELL CONSTRUCTION". 

On the lower benches near San Diego Bay where water may be 
reached at depths of less than about 100 feet, dug wells are practi- 
cable, but such wells can not be constructed profitably on the high 
mesas, and even on the lower benches drilled wells are likely to be 
much more satisfactory. Wells 3J or 4 feet in diameter can be dug 
at a cost of about $1 a foot. 

Very satisfactory results are being obtained on the lower terraces 
by the use of cased wells 8 to 12 inches in diameter. Where the 
usual depth to the water plane exceeds 10 feet and ordinary centrifu- 
gal pumps are to be installed, pump pits are dug and the casing sunk 
from the bottom. In the best plants pump pits are lined with con- 
crete. If a deep-well pump is to be installed a pit is not necessary. 



188 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Wells are drilled either with the ordinary California rig or some type 
of portable rig. Occasionally standard pipe is used as well casing 
instead of stovepipe casing. 

Two other general methods of well drilling may be successfully 
employed in the sedimentary formations of this area — the percus- 
sion method and the abrasion or rotary method. The percussion 
method, which is more commonly used, consists of lifting and 
dropping, by means of suitable apparatus, a heavy string of drill 
tools that punch or cut a hole through the unconsolidated mate- 
rials and break the solid rock into fragments small enough to 
be readily removed from the hole. When the well is drilled in uncon- 
solidated materials iron pipe or well casing as large in diameter as 
the hole will admit, usually 6 to 10 inches, is generally driven down 
as rapidly as the drill descends, each added length of casing being 
securely screwed to the preceding one to make a tight joint. If the 
well penetrates hard bedrock the casing should be driven a few feet 
into the rock to prevent infiltration of water and silt from the over- 
lying deposits. If the well ends in loose material the casing extends 
to the bottom of the hole and may be perforated or slit at the lower 
end to admit water more readily. The casing is allowed to extend 
several inches above the surface of the ground to prevent inflow of 
surface water, and a flange is fitted to the top to which a pump is 
attached. 

In drilling by the abrasion method hollow drill tools armed with 
some harder materials, such as diamonds or chilled shot, are rotated 
on the rock in such a way that a cylindrical core is cut out and 
brought to the surface in short pieces. The wells sunk by this 
method are finished in the same way as those made by percussion 
drilling and the costs practically the same as those sunk by the other 
method. 

Owing to the competition among well drillers there is no standard 
scale of prices for well drilling. It is customary to charge according 
to a "sliding scale" a certain amount — $2 or $3 a foot for the first 
100 feet and an additional $1 or $2 a foot for each additional 100 
feet. Mr. Wilkes James stated that his rates for a 10-inch well are 
$2 a foot for the first 100 feet, $2.50 a foot for the second 100 feet, 
and $1 a foot additional for each additional 100 feet. This price, 
however, does not include casing. In November, 1914, the price of 
standard 10-inch casing was about 90 cents a foot. 



GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 189 

GROUND WATER IN THE HIOHTiANP AREA. 

By A. J. Ellis and C. H. Lee. 
WATER-BEARING FORMATIONS. 

The rocks of the highland area may be divided, according to their 
ability to store and yield water, into four groups: (1) the crystalline 
rocks; (2) the talus at the bottoms of the mountain slopes; (3) the 
residuum or weathered material, popularly called "decomposed 
granite," in the highland basins, described on page 71; (4) the 
alluvium in the valleys of the principal streams; and (5) the lake 
deposits in Warners and San Felipe valleys. 

WATER IN CRYSTALLINE ROCKS. 

None of the wells that were examined in San Diego County obtain 
water from the crystalline rocks, and this discussion is therefore based 
on the knowledge of the occurrence of water in crystalline rocks in 
other areas; but since the underlying principles do not change from 
one place to another, and since, as will be shown, specific information 
in regard to rock wells is of very little use in planning future develop- 
ments except as emphasizing the uncertainties involved, information 
based on conditions in areas of similar rocks may properly be applied 
to the crystalline rocks of San Diego County. 

Undecomposed crystalline rocks are practically impervious. They 
absorb some water, but the pores that take up the water are so 
small that the movement of water through them is exceedingly slow 
and they are altogether incapable of yielding a water supply when 
the rocks are penetrated by a drill hole. All such rocks, however, 
are more or less broken, and fissures of various sizes extend from the 
surface downward and intersect each other in such a way that a 
drill hole is able to drain not only the intersected fissures but also 
others with which these fissures may be connected. Water finding 
its way into cracks at the surface and passing from one fissure to 
another as it descends may therefore constitute an important source 
of supply. Under these conditions obviously the chief factors in the 
occurrence of water are the number and size of the rock fissures, topo- 
graphy, and the amount of precipitation. In Connecticut, 1 for ex- 
ample, where rock fissures are numerous and the average annual 
rainfall is 47 inches, the average yield of wells drilled into crystalline 
rocks is about 15 gallons a minute; but the range is from nothing to 
more than 100 gallons a minute, and it is a common experience to 
obtain good wells 100 or 200 feet deep within a few yards of per- 
fectly dry holes of greater depth. It is highly probable that, owing 
to the low rainfall in San Diego County, the average yield of wells in 

1 Gregory, H. E., and Ellis, E. E., Underground waters oi Connecticut, with a study of the occurrence 
of water in crystalline rocks: U. S. Geol. Survey Water-Supply Paper 232, 1909. 



190 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

crystalline rocks will be small and that probably a considerable per- 
centage of drill boles will fail to intercept water-bearing fissures and 
will remain dry. In general supplies larger than those necessary for 
ordinary domestic use can not be expected from such wells. The 
most favorable sites for rock wells are where the rocks are most 
intensely fractured and at low levels where streams or the drainage 
from surrounding slopes may afford more ample recharge of the rock 

fissures. 

WATER IN TALUS. 

Deposits consisting of heterogeneous mixtures of coarse and fine 
rock debris from the mountain slopes have accumulated along the 









;:.'-.-.;.•. .Valley fifl."... 




■:■:■■■■■■:■■ ■iSfe®^V\''- , -\->^ vf-'-slrL'K'-J'r-*'. 



Figure 17.— Diagram showing digitate character of contact between talus slope and valley fill; condi- 
tions favorable for rapid drainage of talus. 

edges of many of the valleys in the highland area. In some places 
where the valley walls slope gently the coarse and fine materials are 
somewhat assorted into layers, but as a rule coarse and fine materials 
have been dropped together without assortment. As the finest 
material in the talus slopes is usually coarser than the alluvium that 
is carried out on the valley floors, the talus is particularly well 
adapted for absorbing water, and its topographic position enables 
water to reach it readily. Talus deposits grow simultaneously with 
the accumulation of alluvium on the valley floors, and their bases 
are interlocked with the alluvium in such a way as to afford especi- 
ally favorable conditions for the seepage of water from the talus into 
the alluvium (fig. 17). Owing to its coarseness and its position the 
talus is not adapted for storing water, and the water that it absorbs 
sinks rapidly and enters the alluvium. Unless there is a covering of 



GROUND WATER IN HIGHLAND AREA. 191 

soil on some higher parts of the slope, which absorbs rainfall and 
discharges it gradually into the talus, or unless the fissures in the 
rocks themselves afford such a supply the talus is not likely to con- 
tain water during dry periods ; for this reason it can not in general 
be regarded as a reliable source of well water. If a well must be 
sunk into such a deposit it should be placed as near the bottom of the 
slope as possible; and if it is practicable to choose a site where the 
well will penetrate alluvium the chances of obtaining a water supply 
are much better. It should be noted, however, that in some places 
peculiarities in the talus itself or in the underlying rock slope, or a 
permanent stream or other source of water may afford conditions 
favorable to the occurrence of a ground-water reservoir. 

WATER IN THE RESIDUUM. 
CHARACTER OF THE RESIDUUM. 

The most important source of ground water in the highland area 
is the residuum or, as it is commonly called, the "decomposed gran- 
ite," which covers the bedrocks in all the highland basins and which 
occurs more or less generally throughout the area. This material 
consists of small lumps or grains of the original crystalline rocks 
that have been disintegrated by the removal or alteration of some 
of their mineral constituents. The disintegration is most complete 
at the surface, where in many places the rock has been completely 
reduced to soil, and it decreases gradually from the surface down- 
ward until, at depths ranging from 3 feet to more than 100 feet, it 
merges with thoroughly indurated rock. Granite is one of the most 
easily altered crystalline rocks and is the most prevalent rock in this 
area, so that by far the largest part of the residuum is derived from 
granite. Figure 18 shows sections of the residuum as determined 
from well logs. 

The porosity of residuum varies greatly as it depends on the 
degree of disintegration, which is subject to wide variations, both 
vertically and horizontally. In one place, for example, a well may 
be easily dug with a pick and shovel to a depth of 50 feet or more, 
whereas in another place only a few rods distant blasting may be 
necessary at a depth of 15 to 20 feet. But as a rule the residuum is 
sufficiently porous and disintegrated to afford storage for water. 
There are many rock basins, such as El Cajon Valley, Escondido 
Valley, Bear Valley, Jam'ul Valley, and Padre Barona Valley, which 
are nearly water-tight and contain considerable disintegrated material 
in which water is stored. Ground water may be drained from a 
large area by sinking wells through the decomposed rock and dig- 
ging tunnels or boring holes at right angles to the slope of the 
surface, as explained on page 194. 



192 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

WATER TABLE. 

The water table in the residuum lies at depths ranging from less 
than 10 to more than 30 feet below the surface of the ground. Fluc- 
tuations of ground-water level from September, 1914, to August, 
1915, were observed in twelve wells as follows: L 40, G 32, L 92, L 
11, H 32, L 24, L 96, P 21, P 2, H 37, H 17, and H 38. Observations 
since 1912 are also available for wells L 92, L 11, and H 32. The 
positions of these wells are shown in Plates XXII and XXIV and full 
information concerning them is given in Table 45. A summary of 
observations, including dates and elevations of maximum water 



Well G36 
Elevation 370 ft. 



Well L24 

Elevation 430 ft. 



Weil L97 
Elevation 525 ft. 



'."'.' ^ -| 



wen L98 

Elevation 490 fi. 






Adobe soil 



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Approximate 
surface 


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zJTHH 


/fed soil 


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subsoil 


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\ f r •-"*'': 


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Depth 50 ft. Depth 49 ft. 


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granJte 



Depth 69 ft. 



Decomposed 
granite (water} 



Depth mn. 



% 
3 

I 

ts 
0> 



160 



Figure 18.— Sections of wells in residuum. 



levels, is given in Table 30 (p. 126). The maximum, minimum, and 
average range of fluctuations observed in wells in 1914-15 are shown 
in Table 32 (p. 133) . The figures there given indicate an annual range 
of 3.0 to 9.4 feet on an average range of 5.85 feet, although the aver- 
age probably exceeds 5.85 feet over large areas. The detailed reoor 
of fluctuations at eight typical wells, as shown graphically in Plat 
XLVII, corresponds generally to that of wells in the fill of themajo 
valleys. Wells that show quick rise at the date of the first stor 
producing run-off, such as well H 87, are near stream channels; 
other wells in open valle}^ and on gentle foothill slopes the wate 
levels are highest in March or April or even as late as May or June 











WATER-SUPPLY PAPER 446 PLATE XLVTI 










Ian. 


Feb. 


Mar. 


Apr 


May 


June 


July 


r Aug. 


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Oct 
















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Jan. 


Feb. 


Mar. 


Apr. 


May 


June 


Ju/y | Aug. 


Sept 


Oct. 


1915 





DIAGRAM SHOWING 

ATIONS OF WATER TABLE 

OBSERVATION WELLS 

\ GRANITE AREAS 

1912 - 1915 

E: Dotted lines connecting observations indicate 

oximate fluctuations during periods for which 

rd is insufficient to show detail. snyder&black,n.y. 



; 


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of San Of ego River. 


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1315 





DIAGRAM SHOWING 
FLUCTUATIONS OF WATER TABLE 

IN OISSKKVATIO.X WELLS 

I.\ GRANITE AREAS 

1912 - 1015 

NOTE: Dotted lines connecting observations indicate 



GROUND WATEE IN HIGHLAND AREA. 193 

SOURCES OF WATER. 

The water in the residuum or decomposed granite is derived (1) 
by absorption directly from rainfall, (2) by absorption from streams, 
and (3) by seepage from irrigated areas. 

Water from streams is absorbed only by material adjacent to stream 
channels. Streams that flow over alluvium recharge the alluvium, 
which, in turn, contributes to the supply of adjacent residuum. 
If the period of flow is short, as it usually is in small stream channels, 
the quantity of water absorbed from this source is small. Seepage 
from irrigated areas forms a large part of the ground-water supply 
in regions where irrigation is practiced, especially where the supply 
is brought in from a distance. As the irrigation season is in the 
summer, replenishment from this source does not occur during the 
same period as that from rainfall and run-off. The water-bearing 
formations are thus recharged throughout the year instead of during 
the rainy season only. The principal areas of residuum in which 
irrigation is practiced are in El Cajon and Escondido valleys. The 
supply of water available from wells in the residuum within and below 
these irrigated areas is the most plentiful and permanent to be 
obtained in that formation in San Diego County. 

The most general and largest source of water in the residuum is 
derived from rainfall, although less than 40 per cent reaches the water 
table. The rainfall map accompanying this report (PI. XV) shows the 
relative quantities available for absorption in different places. Except 
in El Cajon Valley, the average annual precipitation over the larger 
areas of residuum ranges from 15 to 22 inches, depending on the eleva- 
tion. In El Cajon Valley it ranges from 12 to 14 inches. In very 
dry years, two of which may occur in succession, the precipitation 
may be only half of the above quantities (Table 18, p. 84). 

The duty of water for irrigated citrus orchards in this region is 
about 1 foot per year, and for alfalfa -2 to 3 feet. The supply of water 
from residuum, where the only source of replenishment is rain, is 
inadequate for the irrigation of extended overlying areas. Supplies 
for small isolated areas of a few acres, however, may be obtained from 
one favorably situated well with sufficient lateral development to 
permit drawing water from a large surrounding area. The storage of 
ground water is favored by (1) great depth of residuum, (2) position 
at the bottom of a slope, near a stream channel or in a ravine, and (3) 
vegetation and other surface conditions favorable for retarding 
run-off from the slopes or drainage area above the well. 

YIELD OF WELLS. 

The yield of wells has been found to range under different condi- 
tions from very small quantities to as much as 150 gallons per minute 
115536°— 19— wsp 446 13 



194 

(Tables 43, p. 162, and 61, p. 275). The smallest yields are obtained 
from wells without laterals, in shallow decomposed rock or in unaltered 
rock, on upper slopes or in small ravines, or in other places where 
conditions are not favorable for large absorption; the largest yields 
are obtained from wells that penetrate residuum of considerable 
depth, that are provided with lateral tunnels and auger holes, and 
that are situated in valleys irrigated with water from an outside 
source. In general, it may be said that the specific capacity of the 
best wells in residuum is about 8 gallons a minute per foot of draw 
down, that for many wells it is as low as 1 gallon per minute per foot 
of draw down, and that for the poorest wells it is much less than 1 
gallon. 

METHODS OF SINKING WELLS IN RESIDUUM. 

Both dug and drilled wells can be successfully sunk in areas in 
which ground water is derived from residuum, but drilled wells are 
not likely to yield much more water than is ordinarily required for 
domestic use, so that where water is needed for irrigation dug wells 
should be constructed. 

Drilled wells should preferably be 10 or 12 inches in diameter. 
Storage may be provided by drilling to a depth below that of the decom- 
posed rock, but this method is not likely to increase the specific capacity 
of the well. Better results may be expected from a well of large 
diameter drilled to the bottom of the pervious rock than from a well 
of small diameter in which storage is provided by drilling into the 
underlying impervious rock. 

Dug wells of the kind ordinarily used for domestic water supplies are 
suitable for that purpose in the areas underlain by the residuum, but 
they do not yield enough water for irrigation. Wells combining modi- 
fications of this type, however, made by digging horizontal tunnels or 
by boring small lateral auger holes from the bottoms of dug wells, 
afford supplies as large as can possibly be obtained from residuum. 
The tunneled wells are usually made in the following manner : 

A well about 10 feet in diameter is dug to the depth at which the 
rock appears to be practically impervious; this depth varies from 
place to place, but in most places is between 30 and 80 feet. The 
disintegrated rock is easily excavated near the surface with pick 
and shovel but it gradually becomes harder with depth and may 
require blasting through more than half the depth. When the water 
level is reached pumps are started and are kept in operation as 
required until all underground work is completed. At the proper 
depth the work of tunneling is begun. An area about 4 feet wide 
and 6 feet high is laid out on the wall, the lower side being a few feet 
above the bottom of the well, A smalj blast hole, 4 or 5 feet long, 
is drilled horizontally in the center of the area, and a similar hole, 
inclined toward the center one, is drilled at each corner. This arrange- 






GROUND WATER IN HIGHLAND AREA. 195 

ment of blasts is necessary to insure control of the size and shape of 
the tunnel and to minimize the consumption of powder. The holes 
are usually drilled with a small compressed air drill, but at the cost 
of a little more time and labor they can be bored with hand augers. 
After the blast is fired the walls of the tunnel are trimmed and new 
blasts are prepared as before, the tunnel being advanced to its full 
length in this manner. The tunnels are slightly inclined upward 
to permit the water to flow freely toward the well. The rock is of 
such character that the walls and roof stand without timbering, but 
when blasted from the heading it usually falls in small bits on the 
floor of the tunnel and is washed along by the natural flow of water 
to the well where it is shoveled into buckets and hoisted. Smoke 
produced by blasting is removed by reversed blowers. Tunnels up to 
150 feet in length are commonly constructed in this manner. Usually 
two tunnels are dug in opposite directions from the well, but as many 
as three or four are sometimes made. 

The following charges were made in 1914 for wells constructed by 
this method: For sinking wells 10 feet in diameter in residuum, $10 
a foot for the first 10 feet and $2 a foot additional for each additional 
10 feet; for sinking wells in hard unaltered granite, $15 a foot for 
the first 10 feet and $7 additional for each additional 10 feet; for 
digging tunnels in residuum, $5 a foot for the first 10 feet and $1 a 
foot additional for each additional 10 feet. 

The chief advantage afforded by wells of this kind is their large 
storage capacity. A tunnel 4 by 6 feet in cross section has a storage 
capacity of 180 gallons per foot of length, from which it is evident 
that wells having an aggregate of several hundred feet of tunnels are 
capable of furnishing fairly large supplies when the tunnels have 
become filled. 

Wells with lateral auger holes are sunk to the required depth in the 
usual manner and the laterals are bored 3 or 4 feet from the bottom, 
or as near to the bottom as it is convenient to work. A l^-inch or 
2-inch auger is used, to which, as it advances, successive sections of 
hollow pipe are screwed. The length of the sections is limited by the 
diameter of the well, and each section is perforated by a few small 
holes to admit water. The auger is directed upward at a slight 
angle to permit the water to run freely toward the well, and the 
cuttings, entering the end of the pipe, are carried to the well by the 
flow of water, so that it is not necessary to withdraw the auger until 
it has advanced the full distance. Laterals 100 feet long are com- 
monly bored in this manner. Usually several holes are bored in 
different directions from a well. The cost of laterals ranged in 1914 
from 25 to 50 cents a foot, and a workman can make an average of 
about 40 feet a day where the flow of water is strong enough to remove 
the cuttings readily. 



196 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

The advantage in this method of construction lies in the fact that 
at a very moderate cost the yield of a well may be increased several 
fold, but of course wells of this type lack the storage capacity that 
is obtained by tunneling. 

DESCRIPTIONS BY AREAS. 
FALLBROOK AND VICINITY. 

All the wells examined in the vicinity of Fallbrook end in residuum. 
They range in depth from about 30 feet to more than 100 feet and 
furnish supplies ranging from meager amounts, barely adequate 
for domestic needs, to quantities large enough to irrigate 25 acres 
of land. Ample supplies of good quality are, however, obtained 
in all the wells that are favorably situated. Dug wells with lateral 
auger holes or tunnels below the water level (see p. 194) have been 
found to be much more satisfactory than drilled wells, and there are 
said to be no drilled wells in use at the present time. A few wells, 
8 and 10 inches in diameter, were drilled to depths of 100 feet or 
more in Fallbrook but they failed to furnish adequate supplies and 
were abandoned. The depth to water in the wells examined ranges 
from 10 to 68 feet but exceeds 40 feet only in wells at high elevations, 
where less favorable ground-water conditions are to be expected. 
In order to obtain the best results wells should be sunk at low eleva- 
tions where, by the use of lateral auger holes or tunnels, the under- 
ground drainage from long slopes may be intercepted. The following 
wells are typical of this vicinity. Additional data are given in 
Table 46 (p. 221). 

At Dr. Pratt's ranch (B 4) there are three dug wells 8 feet in 
diameter, each 40 feet deep, connected at the bottom by tunnels 
4 feet wide by 6 feet high, with other tunnels, aggregating about 
180 feet in length. These wells end in residuum which was said to 
extend to a depth of 100 feet, where hard blue granite is reached, 
and they furnish enough water to irrigate 25 acres of lemon trees. 
The water stands normally within 10 feet of the top, and it was 
reported to rise to this level rapidly even after the wells had been 
pumped empty. No timbers or other supports are used in the 
tunnels and the wells are curbed to a depth of only 15 feet. Water 
is pumped at the rate of about 135 gallons a minute at a cost of about 
3 cents per 1,000 gallons. 

Mr. J. A. Fulwiler's well (B 5), in the NE. J sec. 25, T. 9 S., R. 4 W., 
is a dug well 55 feet deep and 4 feet in diameter, at the bottom of 
which is a tunnel 7 feet high, 5 feet wide, and 16 feet long. It 
penetrated gray residuum which required blasting below the depth of 
15 feet, but did not reach solid granite. The well has been pumped 
at the rate of about 35 gallons a minute, 24 hours a day, for 6 weeks, 
and the water level stood constantly 52 \ feet below the surface, or 
2\ feet above the bottom of the well. Very little water is used for 
irrigation at the present time, but it is believed that the supply is 



GKOUND WATER IN HIGHLAND AREA. 197 

sufficient to. irrigate 20 acres. The pumping plant consists of a 
suction pump with two 3 -inch cylinders 22 inches long, and one 
4-horsepower gasoline engine. 

This well is near the bottom of a slope about one-fourth mile long, 
near the top of which is a dug well 13 feet deep, containing 5 feet of 
water and yielding just enough for domestic use. It can be pumped 
empty in a short time by a windmill operating a 2-inch cylinder. 
Mr. Fulwiler stated that the well passed through 15 feet of soil at the 
surface and continued to the depth of 73 feet through residuum. 

ESCONDIDO AND VICINITY. 

Escondido Creek flows over a deposit of valley fill that extends to a 
depth of more than 50 feet below the present floor of the valley. 
This deposit consists of beds of sand and gravel and a few layers of 
hard clay. Its areal extent has not been accurately determined but 
it is probably not more than a half mile wide and about 5 miles long. 
Wells along the creek between Escondido and the north side of the 
plain derive their water from the valley fill, but all other wells in the 
vicinity obtain their supplies in residuum. 

Well G 1, belonging to A. C. Meyer, is 38 feet deep and 4.5 feet in 
diameter. Residuum extends from the surface to the bottom of the 
well where the material is unaltered granite. Two horizontal tunnels, 
3 feet wide by 6 feet high, one of which is 165 feet long and the other 
38 feet long, extend in opposite directions from the bottom of the 
well. The pumping plant consists of a 9-horsepower gasoline engine 
and a No. 3 vertical centrifugal pump. The well can be pumped at 
the rate of 180 gallons a minute for six hours daily. 

George Lehner's well (G 6) is a dug well 61 feet deep and ends in 
residuum. Two horizontal tunnels, 3 feet wide and 6 feet high, 
extend from the bottom of the well 60 feet in opposite directions. 
The pumping plant consists of a 6-horsepower gasoline engine and a 
suction pump with a cylinder 6 inches in diameter and 36 inches long. 
The well is said to have a continuous yield of about 18 gallons a 
minute, but it is allowed to stand idle until it has accumulated con- 
siderable water and is then pumped at the rate of about 45 gallons a 
minute for about 12 hours, when the supply becomes exhausted. 

A drilled well (G 8) 51 feet deep, at the home of Mr. J. C. Dickson, 
about 1£ miles northeast of Escondido post office and just south of 
Escondido Creek, penetrated the deposits shown in the following log. 

Log of well of J. C. Dickson (G 8), about 1\ miles northeast of Escondido post office. 

Depth. 
Ft. in. 

Soil and sand 20 

Tough plastic clay 21 6 

Sand 22 6 

Gravel, water bearing 30 6 

Tough plastic clay 31 6 

Sand and gravel, little water 51 

Surface of granite bedrock. 



198 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

A well about 100 feet south of this well encountered granite at a 
depth of 5 feet. 

Mr. Dickson's principal water supply is obtained from a well 
drilled about 6 feet from the 51-foot well. It is 31 feet deep and 12 
inches in diameter and on November 19, 1914, the water stood 
7 feet below the surface. It is cased with stovepipe casing and yields 
about 165 gallons a minute. Water is lifted by means of a centrifugal 
pump, operated by a 6-horsepower gasoline engine. A pumping 
test made November 19, 1914, showed that this plant lifted water 
at the rate of 106.5 gallons a minute, and that the drawdown after 
pumping 20 minutes was 10.4 feet. Water is used for domestic supply 
and to a moderate extent for irrigation. 

Well G 10, owned by Mr. John L. Ellis, is about 1 mile southeast 
of Escondido post office. It is 30 feet deep and yields about 20 
gallons a minute. A horizontal auger hole, 1J inches in diameter and 
50 feet long, bored near the bottom of the well, yields a considerable 
part of the water. The water level is ordinarily about 9 feet below 
the top of the well but it is lowered to the bottom in three hours by 
pumping at the rate of 50 gallons a minute. A suction pump with a 
cylinder 5 inches in diameter and 16 inches long is operated by a 
gasoline engine. The water is used principally for domestic supply. 

The dug well of Mr. D. T. Marlor (G 12), which is about 2 miles 
west of Escondido, penetrates residuum to the depth of 25 feet. It 
has no lateral tunnels or auger holes. In April, 1914, the water 
stood 4.8 feet below the ground surface, and on November 20 it stood 
16.8 feet below the surface. This difference in level is believed to 
represent approximately the average annual fluctuation of the ground- 
water level at this place. The yield of the well is very small, but is 
sufficient for domestic needs. A 2,000-gallon tank is filled once a 
week, the water being lifted by means of a suction pump operated by 
a 2-horse-power gasoline engine. 

Well G 13, belonging to Mr. Benjamin Chubbic, is 29 feet deep and 
3 feet in diameter, and on November 20, 1914, the water stood about 
22 feet below the surface of the ground. 

This well also is without tunnels or auger holes and yields only a 
small supply. When pumped at the rate of 3.5 gallons a minute, it 
ususally becomes empty in about an hour. 

The combination well (G 14) of Mr. William Riezebus furnishes a 
supply sufficient for domestic use and stock and for the irrigation of 
10 acres of lemon trees. It consists of two vertical shafts, 40 feet 
deep, 10 feet apart, connected with each other by a lj-inch auger 
hole, and with a system of 565 feet of laterals. Horizontal auger holes 
extend from the bottom of each well, and, to provide storage, a 
horizontal tunnel 3 feet wide, 6 feet high, and 65 feet long, extends 
from the bottom of one of the wells. The pumping plant consists of a 



GROUND WATER IN HIGHLAND AREA. 199 

suction pump and a 6-horsepower gasoline engine. Water is pumped 
at the rate of 54 gallons a minute. The total cost of the well and the 
pumping plant was $1,400. 

POWAY VALLEY. 

Most of the wells in Poway Valley are dug wells, 25 to 50 feet deep, 
without laterals. They end in coarse alluvium or residuum. These 
wells generally yield enough water for domestic use but not enough 
for irrigation. It has been shown, however, by two wells at the head 
of* the valley that supplies adequate for irrigation may be obtained if 
proper methods are used. These wells were dug by Mr. Rufus 
Nephew, one of them (K 13) for Mr. A. A. Flint, and the other (K 14), 
about a half mile east of K 13, for Mr. J. D. Sylvester. Vfell K 13 is 
10 feet in diameter and 66 feet deep and has at the bottom two hori- 
zontal tunnels, in most places 4 feet wide and 6 feet high but locally 
as large as 6 by 10 feet, one of which extends 120 feet north and the 
other 90 feet south. The well penetrated 12 feet of soil, 24 feet of 
sand and gravel, and 30 feet of residuum and did not reach unaltered 
rock. Water was obtained at a depth of 17 feet, and it ordinarily 
stands at this depth when the pump is not operated. A 3-inch 2-stage 
vertical centrifugal pump, set 53 feet below the surface, is run by a 
gasoline engine. The capacity of the pump is 225 to 270 gallons a 
minute. The water level is lowered from 17 feet to 53 feet below the 
surface during 1 1 hours of pumping at full capacity. 

Seven acres of alfalfa are now under irrigation from this well, but 
it is planned to irrigate an additional 15 acres. The water is distrib- 
uted in the following manner: A line of 6-inch galvanized-iron pipe 
in convenient lengths is laid along the higher side of the irrigated 
tract from the well to the lower end of the field and the pump is 
started. The joints in the pipe line are not tight and a certain amount 
of water escapes at each joint but, owing to the volume of the stream 
and the grades, most of it goes through to the end of the line. The 
workman then returns from the pump to the end of the line, the time 
required for this trip being sufficient to allow the proper quantity of 
water to flow from the end of the pipe, and carries each successive 
length of pipe to a parallel position at a suitable distance, say 50 feet, 
from its former place. Thus a new line is formed more or less parallel 
to the first line, and each time a length of pipe is carried to the new 
line the water escapes one joint nearer to the well in the old line. 
The quantity of water that escapes while a length of pipe is being 
moved, with the quantity that previously leaked from the joint, is 
sufficient to cover the space between the pipe lines. When the length 
of pipe nearest the well is moved the water begins to flow through the 
new line and the process of moving is repeated. 

The labor involved in this process is reduced as the distance 
between successive positions of the pipe line is increased, and there- 



200 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

fore in order to minimize the labor two or three pipes are repeatedly 
adjusted at the end of the old line each time it is shortened, in such 
a way that the end of the old line slowly describes an arc, thus 
increasing the width of the strip watered. This method of irrigation 
is employed in many places in San Diego County and it is regarded as 
particularly applicable where soils are very porous. By telescoping 
the pipes so as to make fairly tight joints water may be carried over 
ground at elevations higher than the well. It is said that under 
favorable conditions lifts of as much as 30 feet can be accomplished, 
but such high lifts are ordinarily not economical. 

The following information in regard, to Mr. Sylvester's well (K 14) 
was obtained from Mr. Flint. This well is 10 feet in diameter and 
63 feet deep, with three tunnels 4 feet wide and 6 feet high extending, 
respectively, 30 feet east, 50 feet south, and 150 feet north. A pump 
having two 6-inch cylinders set 3 feet below the tops of the tunnels 
is run by a 10-horsepower gasoline engine. Water is lifted at the 
rate of 90 gallons a minute and the water level has not been lowered 
to the tunnels, although this rate of pumping has been continued 
15 hours a day for 15 days. Twenty-five acres of lemon and apricot 
trees are irrigated. 

RAMONA AND VICINITY. 

A narrow deposit of water-bearing alluvium occurs along Santa 
Maria Creek, but most of the ground water is obtained from residuum. 
The following ground-water developments are typical of this vicinity. 
Data in regard to additional wells are given in Table 46 (p. 221). 

Well H 7, on Mr. Ferdinand Hauck's ranch, was under construction 
when visited, November 23, 1914. It had reached the depth of 23 feet 
and had encountered water at the depth of 14 feet. It was 6 feet 
square and was to be sunk to the depth of 75 feet. There are three 
drilled welis 8 inches in diameter respectively 36, 48, and 60 feet in 
depth, within a few rods of the dug well. Water was reached at the 
depth of 10 feet in each well and the yield of each was adequate for 
domestic use, but the combined yield was insufficient for irrigation. 
Windmills are installed over two of the wells and water ' is pumped 
for domestic use and for stock. 

Well H 8, on Mr. W. D. Dukes's ranch, is a dug well 45 feet deep, 
in the bottom of which is a vertical hole drilled to the depth of 86 feet 
and ending in residuum. When examined this drill hole was about 
fhled with sediment and yielded no water, but before it became 
filled it yielded a supply adequate for domestic use. Four 2-inch 
laterals, respectively 30, 40, 60, and 80 feet long, extend from the 
well at the depth of 40 feet below the surface. The 60-foot lateral 
discharges a 2-inch stream of water which reaches to the center of the 
well. The depth to water below the ground surface on November 
23, 1914, was 9 feet. It was said that water can be reached at any 
place in this vicinity at depths ranging from 6 to 15 feet below the 



GROUND WATER IK HIGHLAND AREA. 201 

surface. The pumping plant consists of a 4-horsepower gasoline 
engine and a lj-inch centrifugal pump. Mr. Dukes stated that in 
this vicinity the alfalfa crop averaged 4 tons per acre without irri- 
gation and 6 tons per acre with irrigation, but, that, regardless of 
production or crops, irrigation was practically essential in order to 
destroy gophers which infest this valley. 

A group of four drilled wells (H 12) on the ranch of Mr. W. E. Wood- 
ward, 8 inches in diameter and ranging in depth from 34 to 38 feet, 
yield water for domestic use and for the irrigation of 15 acres of land. 
These wells are close to Santa Maria Creek and extend through 
valley fill just to the surface of residuum. The depth to water is 
about 9 feet, and the entire supply, amounting to about 585 gal- 
lons a minute, is derived from the valley fill. The wells are fitted 
with perforated casings. The pumping plant consists of a 10-horse- 
power gasoline engine and a 4-inch centrifugal pump. 

Three wells (H 11), belonging to Mr. A. U. Woodward, were 
recently completed a short distance south of H 12, close to Santa 
Maria Creek. They were drilled, 8 inches in diameter, to depths 
of from 34 to 36 feet, and just reach the surface of residuum under- 
lying the valley fill. Perforated casings extend to the bottoms of 
the wells. Water was reached at the depth of 6 feet and a combined 
yield of 630 gallons a minute was obtained. An 8-horsepower 
gasoline engine and a 4-inch centrifugal pump have been installed 
to pump water for domestic use and for irrigation. 

EL CAJON VALLEY. 

Along the north side of ElCajon Valley water is obtained from the 
valley fill along San Diego Eiver, as described on page 119. South of 
the filled valley of the San Diego, however, ground water is obtained 
principally from residuum. The usual practice in this valley is to 
dig wells 5 feet in diameter to depths 30 or 40 feet below the water 
table, then to bore near the bottom three or four horizontal auger 
holes 2 inches in diameter. It has been found that by boring these 
holes the yield of a well is increased two or four fold, affording on 
the average about 45 gallons per minute. A few of the older wells 
in the valley have lateral tunnels, of large cross section below the 
water table, but although the advantage of a large storage capacity 
in this sort of well is recognized, auger holes are now made in pre- 
ference to larger tunnels because of the great difference in the cost of 
construction (p. 195). A large number of the wells in El Cajon 
Valley are equipped with pumps operated by gasoline engines, and it 
is said that on this account the water table has been very considerably 
lowered. Mr. H. Culbertson, who has drilled many of the wells in 
the valley, stated that 50 years ago water was reached at the depth 
of 8 feet on the* east side of the valley where it now stands at a depth 
of 40 feet. Moreover, the flume owned by the Cuyamaca Flume Co., 



202 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

of San Diego, extends along the east and south sides of the valley 
and has supplied water for irrigation since 1887, and it is believed 
that this has contributed materially to the ground-water supply. 

At many places in the western part of the valley wells have pene- 
trated beds of marl interbedded with and underlying clay at depths 
ranging from 8 to 40 feet below the surface. The marl beds have 
often yielded bitter, salty water, and some wells have been aban- 
doned on this account. The marl beds are not continuous over the 
entire valley, however, but appear to have been laid down in the 
depressions on an uneven basement between which masses of granitic 
residuum rise to the surface of the ground. Water obtained from 
the granite has invariably been of good quality. 

Well L 24, owned by Joseph Miller, is a mile north of El Cajon in 
El Cajon Valley. The well consists of an open pit, 7.5 feet in diam- 
eter and 50 feet deep. About 7 feet up from the bottom of the well, 
five 2-inch auger holes have been bored, extending out radially from 
the well and sloping slightly upward for distances ranging from 60 
to 131 feet. The total length of these laterals is 541 feet. The log 
of the well (fig. 18) shows 32 feet of residuum from which the water 
issues. The normal water level during the year is about 12 feet 
below the ground surface. In a test covering 20 hours and 48 
minutes the well was pumped at the rate of 156 gallons a minute, 
during which time the water level was lowered 20.8 feet or to a level 
30.8 feet below the surface of the ground. The capacity of the v/ell 
is therefore 7.5 gallons a minute per foot of drawdown. 

Well L 98, owned by Charles Bentley, is 2 miles east of El Cajon. 
It consists of an open pit about 7 feet in diameter for the first 6 feet, 
4.5 feet in diameter for the next 20 feet, and 6 feet in diameter for 
the rest, the total depth being 68.5 feet. It has no lateral tunnels or 
auger holes. Its log (fig. 18) , shows 62.5 feet of residuum, from which 
the water issues. Its normal water level is about 11 feet below the 
ground surface. In a test covering 3 hours and 30 minutes the well 
was pumped at an average rate of about 79 gallons a minute. The 
total draw down was 24.7 feet or to a level about 36 feet below the 
surface of the ground. The capacity of the well is therefore only 
3.2 gallons a minute for each foot of drawdown, or less than half the 
specific capacity of well L 24, which has a large system of laterals. 

PADRE BARONA VALLEY. 

The floor of Padre Barona Valley is composed of residuum which 
in some places is covered by thin deposits of alluvium and every- 
where underlain by hard blue granite. The residuum ranges from 
30 to 40 feet in thickness and is saturated with water below a depth 
of 8 feet from the surface of the ground. A number of wells have 
been sunk to obtain water for irrigation. 



GROUND WATER IN HIGHLAND AREA. 



203 



As Barona ranch, owned by Mr. W. H. Jones, includes all the land 
in the valley, the systematic development of the ground-water 
resources is unhampered by conflicting rights and requirements. It 
is planned to dig wells at convenient intervals entirely across the 
valley and to connect them by tunnels. The description of one of 
the wells in this proposed series that was under construction when 
visited on October 27, 1914, is applicable to all the wells now in the 
valley. This well is 39 feet deep and 10 feet in diameter, with two 
tunnels 4 feet wide, 6 feet high, and 125 feet long, one extending north 
and the other south from the bottom of the well. It penetrates 
residuum and extends to comparatively unaltered rock. This well 
reached water at a depth of about 8 feet and yielded at the time of 
examination 45 gallons a minute, although one of the tunnels was 
only about half completed. The probable quantity of water obtain- 
able from the completed system had not been estimated but it was 
expected to be sufficient to irrigate all the overlying lands. 

WARNERS VALLEY. 

No wells have been drilled in Warners Valley to obtain water sup- 
plies, but in 1912 and 1913 Mr. Winterhalter sank a number of test 
holes for the purpose of obtaining information in regard to the 
position and fluctuation of the water table. The positions of these 
test holes is shown on Plate II, and the results of the measurements 
of the depths to water, as furnished by Mr. Williams Post, are shown 
in the following table: 

Table 44. — Depths to the water level in test holes on the Warner ranch. 

Hole E 1. 

[Elevation, 2,703 feet; depth, 9 feet.] 



Date. 


Depth to 
water 
level. 


Elevation 

of water 

level 

above 

sea level. 


Date. 


Depth to 
water 
level. 


Elevation 

of water 

level 

above 

sea level. 


1913. 
Jan. 2 


Feet. 
Drv 


Feet. 


1913. 


Feet. 
Dry. 


Feet. 


14 


...do 




July 1 


.do.... 




24 


...do 




18 


.do 




Feb. 10 


...do 




Aug. 8 


.do 




Mar. 3*. . . . . 


do 




23.... 


do.... 




18 


.do 




Sept. 5 


do.. . 




June 2 


...do 






do... 

















Hole E 2. 

[Elevation, 2,729 feet; depth, 8 feet.] 



Dec. 3.. 


1912. 


6.1 
6.0 

5.7 
5.7 
4.4 
4.4 
1.3 


2,722.9 
2, 723. 

2, 723. 3 
2,723.3 

2,724.6 
2,724.6 
2,727.7 


1913.' 
Mar. 18 


1.6 
3.9 

4.5 
5.1 

5.8 
6.2 
7.4 
7.2 


2,727.4 
2,725.1 
2,724.5 
2, 723. 9 
2,723.2 
2, 722. 8 
2,721.6 
2, 721. 8 


17 






1913. 


17 




July 1 


Jan. 2 . . 


18 


14 


Aug. 8 


30 


Sept. 5 . . 


Feb. 10 


23 


Mar. 3 











204 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 
Table 44. — Depths to the water level in test holes on the Warner ranch — Continued. 

Hole E 3. 

[Elevation, 2,789 feet; depth, 5 feet.] 



Date. 


Depth to 
water 
level. 


Elevation 

of water 

level 

above 

sea level. 


Date. 


Depth to 

water 
level. 


Elevation 

of water 

level 

above 

sea level. 


Dec. 3.. 


1912. 


Feet. 
4.3 
4.2 

4.0 
3.9 
3.2 
3.4 
2.1 
2.3 


Feet. 

2,784.7 
2, 784. 8 

2. 785. 
2,785.1 
2,785.8 
2, 785. 6 
2,786.9 
2,786.7 


1913. 


Feet. 
5.0 
5.3 
5.3 


*Feet. 
2,784.0 
2 783.7 


17 .- 


17... 




1913. 


July 1 


2,783.7 




18 


Dry. 


Jan. 2.. 


28 




Do. 


14 


Aug. 8... 




Do. 


30 


23... 




Do. 


Feb. 10 


Sept. 5 


6.5 
6.3 


2,782.5 
2,782.7 


Mar. 3 


23 


18 









Hole E 4. 

[Elevation, 2,790 feet; depth, 7.5 feet.] 



Dec. 3.. 


1912. 


7.5 
7.5 

7.5 
7.5 
7.1 
7.5 
6.1 
5.8 


2,782.5 
2, 782. 5 

2,782.5 
2,782.5 
2,782.9 
2,782.5 

2. 783. 9 

2. 784. 2 


1913. 


7.1 
7.3 

7.4 
7.7 
7.7 
7.7 
7.7 
8.3 
1.8 


2,782.9 
2,782.7 


17 


17 




1913. 


July 1 


2,782.6 
2,782.3 
2,782.3 
2,782.3 
2,782.3 




18 


Jan. 2 . . 


28 


14 


Aug. 8 


29 


23 


Feb. 10 


Sept. 5 


" 2,781.7 


Mar. 3 . . 




23 


2,788.2 


18.. 









Hole E 5. 

[Elevation, 2,817 feet; depth, 8 feet. 



Dec. 3.. 


1912. 


5.9 

5.7 
5.2 
4.6 
4.0 
1.6 


2,811.1 

2,811.3 
2,811.8 
2,812.4 
2, 813. 
2, 815. 4 


1913. 
Mar. 18 


1.9 
5.5 
6.0 
6.1 
6.2 
6.3 
6.2 
6.1 


2,815.1 
2,811.5 




1913. 


June 3 




17 


2,811.0 
2, 810. 9 

2. 810. 8 
2,810.7 
2, 810. 8 

2. 810. 9 


Jan. 2 . . 


July 1 


14... 


18 


29 


Aug. 8 


Feb. 10 


Sept. 5 


Mar. 3 


23 







Hole E G. 

[Elevation, 2,837 feet; depth, 7 feet. 



1912 

Dec. 3 

17 

1913 
Jan. 2 

14 

30 

Feb. 10 

Mar. 3 

18 



1.8 
1.9 



2.0 
1.8 
2.0 
2.2 
1.6 
2.3 



2, 835. 2 
2, 835. 1 



2, 835. 
2,835.2 
2, 835. 
2,834.8 
2,835.4 
2, 834. 7 



1913 
June 3 

17 

July 1 

18 

28 

Aug. 8 

23 

Sept. 5 .'.'.'.'.'.'.'.'. 
23 



GROUND WATER IN HIGHLAND AREA. 



205 



Table 44. — Depths to the water level in test holes on the Warner ranch — Continued. 

Hole 1 1. 

[Elevation, 2,798 feet; depth, 9 feet.] 



Date. 


Depth to 
water 
level. 


Elevation 

of water 

level 

above 

sea level. 


Date. 


Depth to 
water 
level. 


Elevation 

of water 

level 

above 

sea level. 




1912. 


3.6 
3.6 

3.4 
3.2 
3.1 
3.1 
2.5 


2. 794. 4 
2,894.4 

2,794.6 
2, 794. 8 
2,794.9 
2, 794. 9 

2. 795. 5 


1913. 
Mar. 18 


3.1 

4.4 
4.7 

4.7 
4.7 
4.7 
4.5 
5.3 


2, 794. 9 


17 ... 


June 3 

17 


2,793.6 




1913. 


2,793.3 
2,793.3 
2, 793. 3 




July 1 


Jan 2 


18 


14 


Aug. 8 


2,793.3 


29 


Sept. 4 


2, 793. 5 


Feb 10 


P 23 


2,792.7 


Mar. 3 











Hole I 2. 

[Elevation, 2,986 feet; depth, 9 feet. 



Dec. 3.. 


1912. 


6.9 
8.1 

6.1 
5.9 

5.7 
5.8 
4.2 


2. 979. 1 
2,979.9 

2,979.9 
2,980.1 
2,980.3 

2. 980. 2 
2,981.8 


1913. 
Mar. 18 


3.3 
5.4 
6.0 

7.1 
7.4 
4.7 
8.1 
8.6 


2,982.7 
2,980.6 
2,980.0 
2, 978. 9 


17 






1913. 


17 




July 1 




18 


2,978.6 
2,981.3 
2,977.9 
2,977.4 


14 


Aug. 8 


29 


Sept. 5 


Feb 11 


23 


Mar. 3 









Hole I 3. 

[Elevation, 3,095 feet.] 



1912 

Dec. 3 

17 

1913 
Jan. 2 

14 

24 

Feb. 10 

Mar. 3 



4.6 


3, 090. 4 


4.2 


3, 090. 8 


4.0 


3,091.0 


3.7 


3,091.3 


3.3 


3, 091. 7 


3.1 


3,091.9 


2.5 


3, 092. 5 



1913 

Mar. 18 

June 3 

17 

July 1 

18 

Aug. 8 

Sept. 5 

23 




3,091.9 
3,089.5 
3,088.8 
3,088.5 
3,088.2 
3, 088. 2 
3, 087. 2 
3,087.1 



Hole I 4. 

[Elevation, 2,713 feet; depth, 7 feet.] 



Dec. 3.. 


1912. 


6.4 
6.5 

6.7 
6.9 
6.6 
6.9 
6.3 
4.3 


2,706.6 
2, 706. 5 

2,706.3 
2, 706. 1 
2,706.4 
2, 706. 1 
2, 706. 7 
2, 708. 7 


1913. 
Mar. 18 


3.6 
4.4 
4.7 
4.8 
4.8 
4.9 
5.2 
5.4 
5.8 


2,709.4 
2,708.6 
2,708.3 
2,708.2 
2, 708. 2 
2 708 1 


17 






1913. 


17 , 




July 1 


Jan. 2.. 


18 


14 


Aug. 8 


29 


23 


2, 707.' 8 
2, 707. 6 
2,707.2 


Feb. 3 


Sept. 5 


10 




Mar. 3 









The water table is at shallow depths over a large part of Warners 
Valley, and springs appear at several places in the valley and along 
its borders. There is a group of hot springs at Agua Caliente, just 



206 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



above the eastern margin of the valley, which is generally known in 
southern California as a health resort. The water is sulphurous and 
reaches the surface of the ground with a temperature of about 148° F. 






SAN FELIPE VALLEY. 



The following information in regard to the water supply of San 
Felipe Valley was collected by J. S. Brown, of the United States 
Geological Survey, during a trip through the valley in 1918. 

San Felipe Valley, most of which is included in an early land grant 
known as San Felipe ranch, comprises 15 to 20 square miles of valley, 
inclosed by moderately high mountains, in the eastern part of T. 12 S., 
R. 4 E., and the southwestern part of T. 12 S., R. 5 E. Through 
Banner Creek on the south, the Arkansas and other canyons on the 
west, and the headwaters of San Felipe Creek on the northwest, 
reaching back to the divide by Warner ranch, it receives the drainage 
from an area approximately twice its size, forming the eastern slope 
of moderately high mountains along the Peninsular divide. It 
receives also a small amount of drainage, chiefly intermittent, from 
the eastern and southern slopes. 

Nearly all the western streams are perennial in the mountain 
region, though at places even there the flow is entirely within the 
stream gravels. The largest of these streams is Banner Creek, much 
of whose flow is forced to the surface by a rock dam in the gorge half 
a mile below Banner. A current-meter measurement made here 
February 13, 1918, showed 1.04 second-feet of water, which probably 
represents the usual winter flow. The flow in the upper end of San 
Felipe Creek is probably nearly as great, and that from the western 
canyons as much more. The water supply includes also the sub- 
surface flow and the run-off from occasional floods. 

The upper end of San Felipe Valley, including a stretch 2 miles 
long extending about a mile down into the San Felipe ranch, is 
separated from the larger valley below by low spurs of the inclosing 
mountains. In the upper half of this tract, which is little more than 
half a mile wide, the waters of upper San Felipe Creek sink and leave 
a dry, steeply sloping floor covered with a moderate growth of grass; 
in the lower half mile, over an area comprising probably 160 acres 
in the upper end of the ranch, a rank grove of willows and large 
cottonwoods and increased growth of grass indicate that ground 
water is near the surface ; just below this area a stream nearly equal 
to Banner Creek bursts up from the valley in numerous groups of 
springs that flow for a distance over the low natural dam. 

This water, together with that from Banner Creek and western 
canyons, unites to form a body of ground water under a second 
small valley, whose outer edges grade from rocky fans into grassy 









GROUND WATER IN HIGHLAND AREA. 207 

slopes and give way finally to a marsh in the tract a mile or so east 
of the San Felipe ranch house. Shallow wells of good water are 
easily obtained from the ranch house eastward. One well near the 
house yields a small flow, and four other wells near by or a little 
farther east and fitted with windmills and furnish water for stock as 
well as for the irrigation of small garden plots. 

Another low granite ridge, jutting out from the south, constricts 
the passage of underground waters and separates a third small valley 
(T. 12 S., E. 5 E.) from the one above. The water rising at this 
point, some 2 miles east of the ranch house, appears to flow con- 
tinuously through the lower valley, and ground water is at shallow 
depths over most of the central area. A heavy growth of mesquite 
covers the ground and grass is plentiful, making excellent pasturage. 
Springs that break out at some places indicate a slight pressure on the 
water beneath. The flow of San Felipe Creek near the middle of this 
valley was estimated as at least 3 second-feet by comparing its 
volume with that of Banner Creek. This water at the lower end of the 
ranch spreads out over an alkali flat, probably half a mile in diameter, 
and passes out through a narrow gorge at the northwest, from which it 
sinks into the desert eastward, and does not reappear until well down 
near the Salton Sea, where at places it breaks out for short distances 
as a weak flow of vile, bitter water, utterly unfit for any human use. 

The creek at many places here flows through cut banks 10 to 20 
feet deep which show very evenly stratified fine sands containing 
great quantities of mica and considerable clay. The possibility that 
this "part of the valley is occupied by lake beds is very strongly 
suggested, though no direct evidence was obtained. 

Little use has heretofore been made of the water, the San Felipe 
ranch owners preferring to engage in grazing and using the water only 
for stock. A little of the water that rises over the first natural dam 
is led over some alfalfa ground in the upper part of the central valley, 
and a few other plots are irrigated by water from the wells. Several 
small tracts of excellent soil in different parts of the valley could 
probably be irrigated by proper conservation of the water available. 

All the water, except possibly that obtained in the vicinity of the 

alkali flat, is of good quality. A sample taken from a stock well near 

! the northwest corner of sec. 34, T. 12 S., R. 5 E., near the lower 

ranch gate, should represent probably the most saline water in the 

! valley. A slight taste of salt is noticeable. 

Five wells have been drilled on the San Felipe grant, none of which 

reached bedrock or residuum in place. All are situated near the 

middle of the valley and were intended to furnish water for irrigation. 

The water is said to be of good quality, but the wells were not tested, 

1 and their success as sources of water for irrigation is not known. 



208 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Well I 6, at the ranch house, is a drilled well 280 feet deep, lined 
with 12-inch casing, which was perforated after being inserted. The 
well penetrated alluvial rock debris, sand, and clay, and ended in a 
bed of rounded boulders from which a good supply of water was 
obtained. 

Well I 5, half a mile east of I 6, penetrated alluvial soil and gravel 
to the depth of 90 feet, where it reached a bed of large boulders. 
This well is 12 inches in diameter and is finished in the same manner 
as I 6. 

The other three wells — I 7, I 8, and I 9 — were all similar to those 
described in the preceding paragraphs. 

DETAILED WELL RECORDS. 

Tables 45 and 46 give records of all wells and springs examined in 
San Diego County. 



DETAILED WELL RECORDS 



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-14 



210 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



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DETAILED WELL RECORDS. 



211 



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212 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



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214 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



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215 



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DETAILED WELL RECORDS. 



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222 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

QUALITY OF WATER. 

By A. J. Ellis. 
SCOPE OF WORK. 

The investigation of the water resources of San Diego County in- 
cluded a study of the chemical quality of the waters for the purpose 
of determining their adaptability for use for domestic supplies and 
for irrigation. 

The specific information in this report in regard to the quality of 
the waters is based on analyses or assays of 1 1 1 samples of water col- 
lected by A. J. Ellis and C. H. Lee in November and December, 1914, 
and June, 1915, and of 10 samples collected by F. C. Ebert in 1918. 
The samples collected in 1914 and 1915 were analyzed or assayed by 
S. C. Dinsmore, under contract with the United States Geological 
Survey, and those collected in 1918 were analyzed by Alfred A. 
Chambers and C. H. Kidwell in the laboratory of the water-resources 
branch of the United States Geological Survey. The complete ana- 
lytical data are given in Tables 57, 58, and 59, pages 260-263. 

Seven samples of surface waters, collected in March, 1918, by F. C. 
Ebert, were analyzed by Alfred A. Chambers and C. H. Kidwell and 
are given in Table 56, page 259. 

METHODS OF ANALYSIS AND ACCURACY OF RESULTS. 

The analyses (Table 57, pp. 260-261) were made according to the 
methods outlined in the report on the quality of surface waters in the 
United States Water-Supply Paper 236 (pp. 9-23), except that 
" sodium and potassium (Na + K)" was computed by calculating the 
sum of the reacting values of the acid radicles and subtracting from it 
the sum of the reacting values of the basic radicles determined. The 
excess of the acid radicles divided by the reacting value of sodium is 
considered to be the amount of sodium plus potassium present in 
parts per million. 

Total hardness as CaC0 3 , scale-forming constituents, foaming con- 
stituents, and alkali coefficients were computed according to the for- 
mulas given in this report on pages 225, 243 (Nos. 1 and 3), and 
234, respectively. The probability of corrosion is based on a com- 
putation made by applying formula 4, page 243. 

The laboratory assays (Table 58, p. 262) comprise chemically de- 
termined values of iron (Fe), carbonate (C0 3 ), bicarbonate (HC0 3 ), 
sulphate (S0 4 ), chloride (CI), and total hardness as CaCO s , and com- 
puted values for sodium plus potassium (Na + K), total solids, scale- 
forming and foaming constituents, and alkali coefficient. 

The methods used in determining chloride, carbonate, and bicar- 
bonate are the same in the assays as in the analyses. Sulphate was 
determined by the field method described by R. B. Dole in Water- 
Supply Paper 398 (pp. 42-43); iron was determined by the field 



No. on 
PL II. 



Method of lift, a 



Yield 
(gallons 

per 
minute). 



Use of 
water, b 



Remarks. 



Al 
A2 
A3 
Bl 
B2 
B3 
B4 
B5 
B5a 
B6 
cCl 
dC2 
C3 
Dl 
El 
E2 
E3 
E4 
E5 
E6 

/Fl 

dF2 

dF3 

dF4 

E5 

F6 

cF7 

F8 

«/F9 

Gl 

G2 

G3 

G3 

G4 

G5 

G6 

c G7 

c G8 
G9 
G10 
Gil 
«G12 
G13 
G14 

c G15 
/G16 
d G17 

G17a 

dG18 

G19 

G20 

G21 

G22 

G23 

G24 

HI 

dH2 

<JH3 

dH4 

dH5 

dH6 

H7 



Gas. eng. suet. p. 
-do , 



35 



W 

Dis. eng. suet. p. 
Gas. eng. suet. p. 
W 



D; I. 
D; I. 
D; I. 
I.... 



Gas. eng. suet. p. 
Gas. eng. cent. p. 
Gas. eng. cent. p. 



1.600 
540 



D; I. 
I.... 

D; I. 



Tunnels. 

Two tunnels 4 by 6 feet, 8 feet long. 
180 feet of tunnels, 4 by 6 feet. 
16 feet of tunnels, 5 by 7 feet. 

One tunnel U by 5| feet, 12 feet long. 
One tunnel 30 feet long. 



Stm. eng 

3tm. eng 

W 

Gas. eng. cent. p. 
W 



1,000 
1.800 



P... 
D; I. 



900 



Bucket 

Gas. eng., suet. p. 
Gas. eng., cent. p. 



10 
e45 



D.... 
D; I. 

Not used 



Elec. m. cent. p.. 
W 

Gas. eng., cent. p. 
Gas. eng 

Gas. eng., suet. p. 

....do 



Low. 



Gas. eng., cent, p 



P; D; I. 
D.... 
D; I. 



Gas. eng., suet. p. 

Gas. eng 

Gas. eng., suet. p. 

do 

....do 



JV 

Vv 

pas. eng., cent. p. 

L.do 

■-...do 



W 

Gas. eng., cent. p. 

'....do 

'....do 

'....do 



..do 

..do 

..do 



e corresponding number in Table 59, p. 263. 

td classification see corresponding number in Table 58, p. 262. 



Low. 
55 



400 

270 



D 

D 

D; I.... 



S...., 
D; I. 
D; I. 



900 

495 
990 
150 



900 

400-900 

360 



200 feet of tunne 14 by 6 feet. 



60 feet of tunnel 3 by 6 feet. 



4 tunnels. 

50 feet of l|-mch auger holes. 



65 feet of 3 by 6 feet tunnel; 500 feet of 
lHnch auger holes. 



Son Diego County, Calif. 




?:?s»7^;S; B ;• ;'.,.., "X "" m ' : "*"* 















L 

i. ii. 

£51 
£52 
£53 
£54 
LI 
L2 
L3 
L4 
L5 
L6 
L7 
L8 
<L9 
L10 

Lll 
L12 
L13 
L14 
L15 
L16 
L17 




Method of lift, a 


Yield 
(gallons 

per 
minute). 


Use of 

water, b 


Remarks. 


2/ 
*L 
"p 


is.eng., cent.p 

..do 


2 


I 

I 

Not used 

D 

D 

I 

D;I 

Not used 

I 

I 

D;I 

D 

I 

I 

D;S.... 

I 

I 

I;D 

D;I 

D;I 

D 

D 


Plows 2 gallons a minute. 

250 feet of 4 by 6 feet tunnels. 

Flows 2 gallons a minute. 

Wells connected. 

Four 2-inch laterals, 276 feet total length. 
2-inch diameter, 540 feet total length. 

Three 2-inch auger holes. 
400 feet of l|-inch holes. 

80 feet. 

4 tunnels, 6 by 6 feet. 

57, pp. 260-261. 

58, p. 262. 










45 
1,600 


F 
L 

"s 

"i 

'e 

•- 

I 
"ii 

! 

"i 

s 

"n 

s 

11 


ec.m., cent.p 


is. eng., cent, p 

..do 


/360 

675 

1,800 


ec. m., cent, p 


is. eng., cent.p 

..do 


850 
1,300 




..do , 


300 

1,125-1,260 
1,230-1,350 








L18 




30 


L19 




L20 
L21 




180 


I 


L22 






D 

I 

I 

Not used 


L23 
L24 
L25 


Lee. m., cent, p 

..do... 


90 
161 


L26 







L27 

L28 
L29 
L30 
L31 

L32 
L33 
L34 

L35 


as. eng., cent.p 


160 


P 

D 

D 

D 

I;D 

D 

D 

D; I.... 

D;I.... 


•■".:::::::::::::::::: 




as. eng., suet, p 

as eng., suet, p 


90" 

45 
45 

78 




3c. m., suet, p 


L36 






L37 








L38 
L39 


as eng., cent, p 

..do 


900 
270 


I 

I 

D. ...:.. 
I; D.... 

D 

D 

D;I.... 
D;I.... 
D;I.... 
D;l.... 


L 40 
L41 
L42 
L43 
L44 
L45 
L46 
L47 
01 


and p 


ec. m.,cent. p 


720 






..<io. .*'..... :..:::::: 

..do 


225 
900 
540 
180 

45 

270 
50 


..do 




Ola 


D 

D;I.... 

D 

D 

Inc 

D 

D 

D 

S 


02 

003 
04 
05 
06 
07 
08 
09 
10 
Oil 
12 
012 
12 
13 
14 
15 
16 
17 
018 




is. eng., suet, p 




17 




r 


i 






36 


■ 
















D 

Not used 

D 

Not used 
D 


::::::::::::::::::::: 




















is. eng., suet, p 

..do 

as. eng., cent, p 


70 
"*246' 


D;I 

D; I 

I 

r in Table 
jr in Table 



Table 46.— Records of all welh andsprings that weji i cammed in San Diego County, Calif.- 



, ': 



1 


i- : : : 




1 


■bii.*'::!::::: 


,:; i 


405 


do 


28.4 








as 


*> 


40 


|» 


do 


21.2 


490 


d0 


68.5 


JOS 


do 


30 


Z 


7, ;; , ; 


«" 








385 




20 5 


415 


7,; 1 ;;";,' 1 


™ 


41° 


dSiUS" 


g 




















i; 


!:%,;:::::::: 
















270 




3 24 














*> 


);;;.""' 


n ■ 














170 


I;; 1 ; 


■'i'l 









(A;::::;=,",.'-..:l 




No.o: 
PI. 13 



Method of lift.a 



c o lfs. eng., cent. p. 

d O gucket. 

cO 

c O 2llows. 

o 



02 
O 

o 



5 

dO'J 
dO'J 

dO'J 
dO'J 
dO c 

O ciict. p 
cO " 
cO 

o 

dO 



3|as 



eng., cent. p. 

/ 

lee. m., cent, p., 



dO 4-as. eng., cent, p. 
O $lec. m.,cent. p. 



d O ^as. eng., suet, p 

Oi-.do 

dOf 

«Of 

d O fas eng., cent, p.; W. 



c o las. eng., cent, p — 

c o l-.do 

Oi 

d O 4lec. m.,cent. p 

c O i-.do 

O *as. eng., cent, p 

d O ^as. eng., suet. p. 
hand p. 

O 4Jras. eng., cent. p.. . 
dOi-.do 



04---do 

d05;--.do 

09---do 

c o $lec. m.,cent. p. 
c o $as„ eng., cent. p. 

OfL-.do 



c o #lec. m., cent. p. 
OS-. .do 



c o Sjas. eng., cent. p. 

(Of 

c O $lec. m.,cent. p. 

c o^--.do 

O Sandp 

dO S---do 

oev 

/oe 



3. eng., cent, p.; W 



dO 
O 
O 

cp 

cP 

p 
p 
p 
p 
p 
p 
p 
p 
p 



lee. m., cent. p. 

V 

landp 

.do 

V 

V 



Yield 
(gallons 

per 
minute). 



585 



150 



225-300 
400 



90-100 



53 



372 
100 



225 



900 



900 
2,700 



700 



450 
900 



2,000 



1.2 

p. d. 450 



Use of 

water. & 



(Test- 
hole.) 
..do..., 



(Test- 
hole.) 
..do.... 



D;I... 

D 

D;I... 
D;I... 
P 



I 

Washing 
gravel. 
D;I.... 

I 

D 

I 

I 



I; D. 
I.... 



D;I. 
I 

D; S. 
D I. 

D;I. 
I 



I; r>. 
I.... 



I 

D; S... 

I 

I 

D 

D 

I; D... 

I; D... 



I 

D;I.... 
D 

Bottled.. 

D 

S , 

Not used 

S 

P 

D; S... 
D 



Remarks. 



Flows 80 to 100 gallons a minute. 



lassirication of water, see corresponding number in Table 57, pp. 260-261. 
lassification of water see corresponding number in Table 58, p. 262. 






TABLE 4G.—Reconk of all i:,lh <•„,! : U „ [,,.<),< ih«l »n; <.n, min, il in s,u t . J'i.yo Count;/, Calif— Continued. 






v:;V:;.Y 






,lli , n, l l.-mr> 



~:l— 






i.'-'.'i'-. : .','i" 



. [in- -nn-.,ui;i1.-E.-. 



QUALITY OF WATER. 223 

method described by M. O. Leighton in Water-Supply Paper 151 (pp. 
45-47) ; and hardness was determined by the soap method described 
in the report on standard methods for the examination of water and 
sewage, third edition (pp. 31-34), published by the American Public 
Health Association, New York city. 

" Sodium and potassium (Na + K)" was computed according to 
the formula on page 235. 

" Total solids" was computed according to the formula at the bot- 
tom of page 228; in applying this formula 34 was used as the quan- 
tity of silica, the average content of silica determined by analysis in 
50 ground waters of San Diego County being 34 parts per million. 

The quantities of scale-forming and foaming constituents have been 
computed according to formulas 1 and 3, respectively, page 243. 

The alkali coefficient has been computed according to the same 
formula as was used for analyses (p. 234). 

The probability of corrosion is based on a computation made by 
applying thef ormulaf or assays given in the first paragraph on page 244. 

The following discussion of the general quality of water was written 
by R.B. Dole and is reprinted from " Ground water in San Joaquin 
VaUey, Calif.," by W. C. Mendenhall, R. B. Dole, and Herman 
Stabler (Water-Supply Paper 398) , but matter irrelevant to western 
San Diego County has been omitted. 

STANDARDS FOR CLASSIFICATION. 

MINERAL CONSTITUENTS OF WATER. 

All. natural waters contain dissolved or suspended materials with 
which they have come into contact. They take up such materials 
in amounts determined principally by the chemical composition and 
physical structure of the substances, by the temperature, pressure, 
and duration of their contact, and by the condition of substances 
that they have previously incorporated. For purposes of examina- 
tion the substances that may be present in natural waters are classified 
as suspended matter, such as particles of clay or leaves; dissolved 
matter, either of mineral or organic origin; microscopic animals or 
plants ; and bacteria. The presence of very small animals and plants 
likely to affect the quality of water is determined by microscopic 
examination, and the chance of contracting disease by drinking the 
water is ascertained by bacteriologic processes. The amount and 
nature of the mineral ingredients are most commonly determined by 
estimating the total suspended matter, total dissolved matter, total 
hardness, total alkalinity, silica, iron, aluminum, calcium, magnesium, 
sodium, potassium, carbonate, bicarbonate, sulphate, nitrate, chloride, 
free carbonic acid, and free hydrogen sulphide, these being the ma- 
terials most commonly present and most likely to affect the value 
of the waters. 



224 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

WATER FOR DOMESTIC USE. 
PHYSICAL QUALITIES. 

Entirely acceptable domestic supplies are free from suspended 
matter, color, odor, and taste and are fairly cool when they reach the 
consumer. The more nearly waters fulfill these conditions the more 
satisfactory they are for general use. Suspended mineral matter 
clogs pipes, valves, and faucets, and growths of microscopic plants 
suspended in water frequently cause odors and stains. The outlets 
of some artesian wells are surrounded by growths of microscopic 
organisms, which form tufts or layers in pipes and well casings and 
sometimes clog them. So far as known, such growths do not cause 
disease, but they often impart unpleasant odors that make the water 
objectionable. True color is usually due to dissolved vegetable mat- 
ter and causes serious objection only when it exceeds 20 to 30 parts 
per million. 

BACTERIOLOGICAL QUALITIES. 

Before a water is used for domestic purposes there should be 
reasonable certainty that it is free from disease-bearing organisms 
and that it can be guarded against all chances of infection. The dis- 
ease germs most commonly carried by water are those of typhoid 
fever. The bacilli enter the supply from some spot infected by the dis- 
charges of a person sick with this disease, and, though comparatively 
short-lived in water, they persist in fecal deposits and retain their 
power of infection for remarkable lengths, of time. Consequently, 
water from lakes and streams draining from population centers or 
from irrigated fields should not be used for drinking without purifica- 
tion. . Wells should be so located as to be guarded against the en- 
trance of filth of any kind, either over the top or by infiltration. 
Pumps and piping in the system should also be protected. Water 
from a carefully cased well more than 20 or 30 feet deep is acceptable 
if the well is located at a reasonable distance from privies, cesspools, 
and other sources of pollution. Many open dug wells and pits con- 
structed as reservoirs around the tops of casings are exposed to fecal 
contamination from above or through cracks in poorly built side 
walls. Care should be taken that the casings of deep wells do not 
become leaky near the surface of the ground so as to allow pollution to 
enter. As a matter of ordinary precaution the ground should be kept 
clean and water should not be allowed to become foul or stagnant 
near any well, no matter how deep. If shallow dug wells are neces- 
sary, they should be constructed with water-tight walls extending as 
far as practicable into the well and also a short distance above ground. 
The floor or curbing should be water-tight, and pumps should be used 
in preference to buckets for raising the water. Every possible pre- 
caution should be taken to prevent feet scrapings and similar dirt 



QUALITY OF WATEK. 225 

from getting into the well. Ground water is not only less likely to 
become contaminated when protected from surface washings, air, 
and light, but it keeps better and is less likely to develop microscopic 
plants that give it an unpleasant taste. 

CHEMICAL QUALITIES. 

The amounts of dissolved substances permissible in a domestic 
supply depend much on their nature. No more than traces of 
barium, copper, zinc, or lead should be present, because these sub- 
stances are poisonous; however, their occurrence in measurable 
amounts in ordinary waters is so rare that tests for them are not 
usually made. Any constituent present in sufficient amount to be 
clearly perceptible to the taste is objectionable. Water containing 2 
parts per million of iron is unpalatable to many people and may 
cause trouble by discoloring washbowls and tubs and by producing 
rusty stains on clothes. Tea and coffee can not be made satisfactorily 
with water containing much iron because a black inky compound is 
formed. Four or five parts of hydrogen sulphide makes a water 
unpleasant to the taste, and this gas is objectionable also because it 
corrodes* well strainers and other metal fittings. The amounts of 
silica and aluminum ordinarily present in well waters have no special 
significance in relation to domestic supply. 

Approximately 250 parts of chloride makes a water " salty/' and 
less than that amount causes corrosion. Where the chloride con- 
tent runs as low as 5 or 10 parts in normal waters unaffected by 
animal pollution, the amount of chloride is frequently taken as a 
measure of contamination. But the establishment of isochlors, or 
lines of equal chloride, would be of little sanitary value, because 
many of the ground waters dissolve so much chloride from the silt 
that the small changes caused by animal pollution are completely 
masked. 

Calcium and magnesium are the chief causes of what is known as 
the hardness of water. This undesirable quality is indicated by in- 
creased soap consumption and by deposition on kettles of scale com- 
posed almost entirely of calcium, magnesium, carbonate, and sul- 
phate. Calcium and magnesium, forming with soap insoluble curdy 
compounds that have no cleansing value, prevent the formation of a 
lather until these two basic radicles have been precipitated. Hard- 
i ness is commonly measured by the soap-consuming capacity of a water 
expressed as an equivalent of calcium carbonate (CaC0 3 ), and it can 
be determined by actual testing with a standard solution of soap or 
can be computed from the amounts of calcium (Ca) and magnesium 
(Mg) by means of the following formula : 

Total hardness as CaC0 3 = 2.5 Ca + 4.1 Mg. 
115536°— 19— wsp 446 15 



226 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

If, as Whipple states, 1 1 pound of ordinary soap would soften only 
about 24 gallons of water having a total hardness of 200 parts per 
million, it can readily be seen that the hardness of water is of intimate 
concern. Soda ash (sodium carbonate) is used to " break" or soften 
hard water in order to save soap. Some large cities in other States 
have found it advisable to soften their public supplies instead of 
leaving that task to the individual consumer. 

MINERAL MATTER AND POTABILITY. 

The lower waters are in mineral content the more acceptable they 
are as sources of supply, yet the amount of dissolved substances that 
can be tolerated in drinking water is much greater than that allowable 
in city supplies, for which hardness, corrosion, pipe clogging, and 
general utility have to be considered. Though there are certain 
limits above which the common ingredients are intolerable, these 
limits are not only difficult to ascertain but are also likely to shift. 
A normal water is not a pure solution of one salt, whose physiologic 
effect can be measured, but an indeterminate mixture of solutions of 
several salts whose effects are not easily differentiated. Further, 
though all animals select for drinking waters that are lowest in solids 
and avoid those that are highest, the same animals, when trans- 
ported to districts of poor water, accustom themselves to supplies of 
far greater mineral content than those which before they would not 
touch. Consequently any general limits that may be assigned to the 
various mineral ingredients must be regarded as extremely flexible. 

The immediate consequence of drinking waters too high in mineral 
content is usually diarrhea. Many persons at first afflicted with 
this trouble become accustomed to the new supply and acquire what 
may be termed immunity. Whether other disorders result from 
the continued drinking of such waters is not known; and it is equally 
uncertain whether cattle and horses that so commonly are reported 
to have been killed by drinking strong mineral water were killed by 
the purging produced by the mineral matter in the water or by 
excessive consumption of water itself. It would appear 2 that alka- 
line carbonates are most injurious and alkaline sulphates least in- 
jurious and that alkaline chlorides occupy an intermediate position. 
This arrangement corresponds to the order of the same substances 
in reference to their toxic effect on plants. Waters exceeding 300 
parts per million of carbonate, 1,500 parts of chloride, or 2,000 parts 
of sulphate are apparently intolerable to most people. These limits 
fortunately are far beyond the points where the substances in solu- 
tion are clearly perceptible to the ordinary taste. In conclusion it 
can not be too emphatically stated that the information on this sub- 

1 Whipple, G. C, The value of pure water, p. 26, New York, 1907. 

2 This conclusion is drawn from investigation of quality of waters in San Joaquin Valley by R. B. Dole: 
XJ. S, Geol. Survey Water-Supply Paper 398, p. 77, 1916. 



QUALITY OF WATER. 227 

ject is fragmentary and uncertain and that any limits of mineral 
tolerance are modified by individual idiosyncrasy. 1 

INTERPRETATION OF ANALYTICAL DATA IN RELATION TO POTABILITY. 

CHEMICAL CHARACTER. 

The total amount of mineral matter and the nature of the chief 
constituents in a water comprise the essential information for judg- 
ing its potability in respect to mineral ingredients. 

Silica is usually present in colloidal form and it is relatively con- 
stant in quantity. Calcium and magnesium are similar in many 
effects and they vary in amount together, calcium usually being the 
greater. Sodium and potassium are so similar in effect that they are 
seldom separated in industrial analyses but are reported together as 
sodium. Carbonate and bicarbonate, representing more or less 
conventionally different conditions of carbonate in equilibrium, may 
be considered together under the common term of carbonate (C0 3 ), 
to which bicarbonate is translated by dividing by 2.03. These 
groupings, rendered possible by the usual mode of occurrence of these 
substances and by their effects, greatly simplify classification of 
waters. The alkalies, sodium and potassium, can be computed by 
the Stabler formula already noted. The amounts of the chief acids 
and bases are used in applying the following classification: 

n i • /r\ m (Carbonate (C0 3 ). 
Calcium (Ca) L , , ,, .^ * ! 

The designation " calcium' ' indicates that calcium and magnesium 
predominate, and " sodium" that sodium and potassium predominate 
among the bases; the designation " carbonate," " sulphate," or " chlo- 
ride" shows which acid radicle predominates. Combination of the 
two terms classifies the water by type, and tabulation of the classifi- 
cation can be abbreviated by use of the symbols. The appellation 
Na-C0 3 , for example, indicates that sodium and potassium pre- 
dominate among the bases and that carbinate or bicarbonate, or 
both, predominate among the acids, and that the water would yield 
on concentration and crystallization more sodium carbonate than 
any other salt, though this classification does not in any way show 
the amounts of the salts in solution. 

The numerical preponderance of certain acid and basic radicles 
establishes the nature of many waters, but if further refinement in 
classification is desired comparison can be made of the reacting values 
of the radicles, which are the fundamental bases of the effect of the 
radicles. These values can be computed by multiplying the amount 
of each constituent by its valence and dividing the product by its 

1 For further data see Dole, R. B., Concentration of mineral water in relation to therapeutic activity: 
TJ, S. Geol, Survey Mineral Resources, 1911, pt. 2, pp . 1175-1192, 19X2, 



228 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

molecular weight. The factors given in Table 47 can be used for 
that purpose. The factor for sodium may be used for the combined 
values of sodium and potassium. 

Table 47. — Factors for computing reacting values. 



Basic radicles. 


Factor. 


Acid radicles. 


Factor. 


Calcium (Ca) 


0.0499 
.0821 
.0434 
.0255 


Carbonate radicle (C0 3 ) 


0. 0333 






.0164 


Sodium (Na) 


Sulphate radicle (SO4) 


.0208 


Potassium (K) 


Nitrate radicle (NO3) 


.0161 




Chloride radicle (CI) 


.0282 









TOTAL SOLIDS. 

Total solids can be computed from the data of an assay in several 
ways, one of which is to calculate the probable amount of saline 
residue that would be produced by the acid radicles and to add 
thereto an arbitrary amount for silica, undetermined substances, and 
volatile matter. As potassium has the smallest reacting weight of 
the four common bases the assumptions that equal amounts of sodium 
and potassium are present and that calcium and magnesium are 
absent constitute an extreme condition representing a maximum 
saline residue; similarly, the assumptions that equal parts of calcium 
and magnesium are present and that the alkalies are absent consti- 
tute the condition representing a minimum saline residue. A formula 
based on an average between these two extremes gives an estimate of 
total solids (T. S.) within 15 per cent of the exact value for most 
natural waters. 

T. S.=Si0 2 + 1.73 CO 3 +0.86 HC0 3 + 1.48 S0 4 + 1.62 CI. 

The average content of silica (Si0 2 ) in ground waters of San Diego 
County, as determined from 50 analyses, is about 34 parts per million. 
The estimate of solids should not be expressed more closely than to 
the nearest 10 parts or with more than two significant figures. 

The criteria for classification of water for domestic use includes not 
only the nature and quantity of each constituent present but also the 
total quantity of mineral matter. The following table gives an 
approximate rating for the concentration of water: 

Table 48. — Rating of waters by total solids. 



Total solids (parts per 
million). 


Classification. 


More 
than — 


Not more 
than — 




150 

500 

2,000 


Low. 
Moderate. 
High. 
Very high. 


150 

500 

2,000 





QUALITY OF WATER. 229 

WATER FOR IRRIGATION. 
SOURCE OF ALKALI. 

Many mineral substances are injurious to vegetation, but the only 
ones that are usually abundant enough to demand attention are com- 
pounds of sodium, or, as t/hey are commonly termed, "the alkalies." 
Though potassium in nominal quantity is a plant food, it is usually 
not separated from sodium in commercial analyses of water, the two 
bases being estimated together and reported as sodium; but as the 
proportion of potassium in highly mineralized waters is commonly 
low compared with that of sodium this disregard of potassium does 
not lead to any considerable error in judging the value for irrigation. 
During the natural decomposition or rotting of rocks and soils salts 
of the alkalies, easily soluble in water, are formed. These com- 
pounds are leached from the soil and washed away in regions where 
plenty of rain falls, and consequently they do not become concen- 
trated enough to damage crops; but wherever the rainfall is insuffi- 
cient to effect this removal such materials continually increase, and 
the proportion of them may become so great that plants are stunted 
or killed and the ground becomes unproductive. 

Accumulations of alkali can also be caused in another way. All 
waters that penetrate the ground either naturally or as a result of 
irrigation contain these salts in solution, and evaporation of the 
water, leaving the salts, adds to the supply that has been formed by 
decomposition of rock. 

OCCURRENCE OF ALKALI. 

The soluble salts are not evenly distributed over an area or through 
a given depth, but are ordinarily concentrated in patches near the 
surface. Such patches may be found in slight depressions into which 
mineralized water has seeped or drained and from which it has later 
evaporated. The underground water drawn to the surface by 
capillarity also brings alkali, which becomes concentrated in the upper 
layers of the soil. Where the salts are largely sulphates or chlorides 
the plots are covered with deposits of so-called " white alkali" — 
that is, crystals of alkaline chlorides and sulphates, mostly common 
salt and Glauber's salt; but when much carbonate is present the plots 
are blackened by solution of humus and are termed spots of " black 
alkali." It can readily be understood from the manner in which the 
,:alts are formed and from the possibility of their introduction by 
seepage or irrigation that the alkali content of a soil can progressively 
increase until it reaches a strength that will destroy plants previously 
unaffected. Conversely, a soil that is normally too h,igh in alkali 
can be rendered productive by washing part of the soluble salts out 
of it. 



230 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

If the alkali content of a soil is excessive the growth of cultures is 
retarded or entirely prevented. A still greater amount of salts kills 
the most resistant plants, and the area becomes devoid of vegetation. 
The chief cause of the poisonous action is commonly considered to be 
abstraction of water from the plant roots by change of the osmotic 
pressure, but bad effects are also probably more or less due to corro- 
sion of the plant roots, germicidal action on the soil bacteria, and 
interference with the food supply through solution of humus. 

PERMISSIBLE LIMITS OF ALKALI. 

The cause and the manner of the harmful action are, however, not 
so important at present as the amount of these toxic compounds that 
can be tolerated by crops, for the limit of resistance in soils fixes in 
turn the maximum content of waters that can safely be used for 
irrigation, and it indicates the precautions that must be taken in 
applying the water. Yet it becomes evident from brief consideration 
of the problem that limits of tolerance must be very broadly inter- 
preted and that absolute classification of waters in respect to their 
irrigation value is impracticable. 

Many investigators have studied the effect on plant growth of min- 
eral substances in water solutions, and the excellent work of Kearney 
and Cameron * is typical of these. Experimenting with seedlings of 
white lupine and alfalfa in different strengths of pure solutions, they 
found that the readily soluble salts common in soils are toxic in the 
following order: Magnesium sulphate, magnesium chloride, sodium 
carbonate, sodium sulphate, sodium chloride, sodium bicarbonate, 
and calcium chloride, the first being 200 times as harmful as the last. 
But when similar tests were made in the presence of an excess of 
calcium sulphate and calcium carbonate both the order of toxicity and 
the maximum concentrations in which the seedlings would grow were 
entirely changed. The order and the limits for lupine under these 
conditions are sodium carbonate, 1,560 parts per million; sodium 
bicarbonate, 4,170 parts; magnesium chloride, 9,600; sodium chlo- 
ride, 11,600; calcium chloride about 16,000; sodium sulphate, 21,600; 
and magnesium sulphate, 22,400. Magnesium sulphate, which is 
most toxic in pure solution, is least harmful in the presence of large 
amounts of calcium carbonate and sulphate. The chlorides of 
magnesium, sodium, and calcium follow each other in relative toxicity. 

i Kearney, T. H., and Cameron, F. K., Some mutual relations between alkali soils and vegetation: U. S. 
Dept. Agr. Rept. 71, 1902. 

Cameron, F. K., and Breazeale, J. F., The toxic action of acids and salts on seedlings: Jour. Phys. Chem- 
istry, vol. 8, p. 1, 1904. 

Jensen, G. H., Toxic limits and stimulation effects of some salts and poisons on wheat: Bot. Gazette, 
vol. 43, p. 11, 1907. 

Kahlenberg, L., and True, R. H., The toxic action of dissolved salts and their electrolytic dissociation: 
Bot. Gazette, vol. 22, p. 81, 1896. 

Heald, F. T>., The toxic effect of dilute solutions of acids and salts upon plants: Bot. Gazette, vol. 22 
p. 125, 1896. 



QUALITY OF WATER. 231 

The sulphate was found to be the least harmful of the sodium salts, 
sodium chloride being twice and the carbonate fourteen times as 
poisonous. These alterations are extremely significant, for none of 
the salts occurs in large amount in soils except in the presence of 
large quantities of calcium and more or less of all the other harmful 
salts. Therefore the death point in a simple solution of one salt is 
not a safe measure of tolerance, for the power of resistance under 
natural conditions depends on complex reactions between all the 
components of the soil solution. 

Other investigators have shown not only that different cultures 
have different degrees of resistance but also that the order of toxicity 
of the various salts is changed. Some species of rather weak tolerance 
have also been bred to withstand high concentrations, and it is a mat- 
ter of ordinary observation in regions of alkali that certain crops die 
on land where others flourish. The vertical position of the soluble 
salts also is important. Where, as under ordinary conditions, they 
are concentrated near the surface they can do the greatest amount of 
damage because they are in contact with the delicate roots. But they 
may.be washed downward out of the danger zone by proper applica- 
tion of water. All these considerations make it evident that the 
nature of the crops, the manner of cultivation and irrigation, the 
other mineral components of the soil, and many other factors affect 
tolerance to alkali; when the effects of reactions between the mineral 
constituents of the soil and of the applied water are added to these 
modifying features it must be admitted that all general conclusions 
regarding the potential value of a water supply for irrigation are sub- 
ject to much modification in particular cases. 

Possibly the best basis for conclusions on the value of water for 
irrigation is the work of Loughridge, 1 who has endeavored to deter- 
mine the greatest amounts of alkali in the upper 4 feet of ground in 
the presence of which cultures grow and come to maturity. In pursu- 
ance of this plan observations were made of the condition of fruit 
trees, shrubs, cereals, and other cultivated plants growing or dying 
in soils which were then partly analyzed. Loughridge's results are 
of great practical interest because they are linked with observations 
on cultures growing under natural conditions on a large scale, and they 
are here particularly valuable because they represent experiments 
mostly in the territory covered by this report. Interpretation of the 
figures is complicated, however, as Loughridge points out, by uncer- 
tainty as to whether the observed poor growth was always due to 
presence of alkali and not to other harmful conditions. As not one 
alone but all the salts are present in natural soils and as they owe 

i Loughridge,, R. H., Tolerance of alkali by various cultures: California Univ. Agr. Exper. Sta. Bull. 
133, 1901. Quoted by Hilgard, E. W., Soils, p. 467, New York, Macmillan Co., 1906. See also California 
Univ. Agr. Exper. Sta. Bulls. 128, 140, and 169. 



232 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

their toxic action to the extent to which they are dissociated, the 
impossibility of determining the exact amounts of the different salts 
in solution or the share of each acid and each basic radicle in the toxic 
action is fully apparent. Notwithstanding these doubtful points 
much can be learned from the studies regarding the relative tolerance 
of cultures. 

The amount of alkali that could be tolerated was found to depend 
largely on the distribution of the salts in the vertical soil column, the 
injury usually being greatest in the upper foot, where the feeding roots 
and the greatest amount of alkali occurred together. The range of 
tolerance for different cultures is very great. Lemon trees, considered 
very sensitive, were unaffected in the presence of 5,760 pounds of 
alkali per acre 4-feet, while grapevines withstood nearly eight times 
as much, or 45,760 pounds. Sorghum flourished in soil containing 
81,360 pounds per acre 4-feet, but rye withstood only 12,480 pounds 
of alkali. The fact that some plants are more readily affected when 
they are young is well illustrated by alf alf a, which tolerates more than 
eight times as much alkali when old as when young. Experiments in 
vineyards showed that different varieties are affected to different 
degree by alkali and as a corollary that alkali changes the composition 
of grapes. 

RELATIVE HARMFULNESS OF THE COMMON ALEALIES. 

Though various cultures are affected in different degree by sodium 
in the three common forms of carbonate, chloride, and sulphate, there 
is some general agreement. Sodium as the carbonate is commonly 
the most harmful, as the chloride somewhat less so, and as the sul- 
phate least harmful. Hilgard x gives the maxima for cereals grown 
on a certain sandy loam as about 0.1 per cent of sodium carbonate, 
0.25 per cent of sodium chloride, and 0.48 per cent of sodium sulphate, 
corresponding to a toxicity ratio expressed in terms of sodium of 
I : 1.6.: 3.6. The relative harmfulness of sodium in the sulphate, 
chloride, and carbonate, respectively, can be expressed according to 
Loughridge's results for 10 standard crops of San Joaquin Valley by 
the ratio 1:5: 6.6; that is, sodium as the carbonate is 6.6 times as 
harmful, and sodium as the chloride 5 times as harmful as sodium 
as the sulphate. A similar ratio for the 15 most sensitive crops is 
1 : 5.3 : 6.4. If, therefore, sodium as the sulphate is given a toxicity 
of 1 a reasonably approximate estimate of the relative toxicity of 
sodium as the sulphate, chloride, and carbonate, respectively, would 
be expressed by the ratio 1:5:6. Stabler has used in his formulas, 
quoted later, the ratio 1 : 5 : 10 in order to allow for the undesirable 
puddling of the soil by the carbonate. 

i Hilgard, E. W., Soils, p. 484, New York, Macmillan Co., 1906. 



QUALITY OF WATEK. 233 

RELATION BETWEEN APPLIED WATER AND SOILS. 

When water used in irrigating evaporates from the surface of the 
soil it leaves in the ground its content of salts. If all the applied 
water were to escape by evaporation, constant use of any supply, no 
matter how pure it might be, would eventually result in an accumu- 
lation of alkali that would render the soil unproductive. If, on the 
other hand, all of a water not too high in mineral content were to 
seep downward into the deep-lying strata it would leach out the 
soluble salts of a highly charged area, which would thus be made 
productive. Such extreme conditions, however, are not natural. 
Though evaporation greatly exceeds rainfall in arid regions, and the 
accumulation of alkali is thus facilitated, part of the water seeping 
away carries with it a load of salts in solution. Various amounts of 
mineral matter are also taken up by crops and are removed during 
harvesting; then, too, the sodium in the soil and in the applied water 
can be prevented by proper methods of irrigation and drainage from 
accumulating where it will damage the delicate feeding roots of cul- 
tures. Consequently, waters of a relatively low mineral content may 
be applied year after year without inflicting damage, but those 
exceeding a certain limit of mineral content are useless for irrigation ; 
waters of an intermediate class, normally capable of increasing the 
alkalies in the soil, may be harmless under judicious usage. This 
outline of the general relations between the saline content of soils 
and of waters used on them indicates other allowances that should 
be made in estimating to what extent the mineral matter in applied 
waters affects their value for irrigation. 

NUMERICAL STANDARDS. 

Twelve hundred parts per million of mineral matter is the limit of 
concentration given by Hilgard 1 for irrigation water in all cases under 
the ordinary practice in California. This limit is greatly modified by 
the character of the dissolved salts, and the results of extensive irri- 
gation elsewhere indicate that very much stronger waters can be 
used on some soils if they are properly applied. Basing his compu- 
tations on Loughridge's determinations of tolerance, 2 Stabler 3 has 
developed formulas for rating waters in respect to their value for 
irrigation. His comparison is made by means of an " alkali coeffi- 
cient" (k), which is defined as the depth in inches of water which 
would yield on evaporation sufficient alkali to render a 4-foot depth 
of soil injurious to the mose sensitive crops. The sodium equiva- 

iOp.cit.,p. 248. 

8 Loughridge, R. H., Tolerance of alkali by various cultures: California Univ. Exper. Sta. Bull. 133, 
1901. 

3 Stabler, Herman, Some stream waters of the western United States, with chapters on sediment carried 
by the Rio Grande and the industrial application of water analyses: U. S. Geol. Survey Water-Supply 
Paper 274, p. 177, 1911. See also Eng. News, vol. 64, p. 57, 1910. 



234 

lents of the three common salts of sodium, the sulphate chloride, 
and carbonate, are assigned relative toxicities of 1, 5, and 10, respec- 
tively, and the maximum tolerance of sensitive cultures is taken as 
1,500 pounds of sodium in the form of sulphate per acre 4-feet. The 
correctness of the latter assumption by itself might be questioned in 
view of the fact that Loughridge's figures for cultures at the lower 
end of his lists are particularly liable to upward revision after further 
investigation. Yet this should not lead to appreciable error as the 
chief value of the formulas rests in the ratio of toxicities and the 
interpretation of the computed value of lc. 

2 040 
If Na— 0.65 CI is zero or negative, Tc = p, • 

If Na— 0.65 CI is positive but not greater than 0.48 S0 4 , lc = vr X^AOl * 

If Na-0.65 Cl-0.48 S0 4 is positive, fc = Na _ , 32 Cl-0.43 SO/ 

The alkali coefficient, lc, is in inches, as already explained ; the sym- 
bols S0 4 , CI, and Na represent, respectively, the amounts in parts 
per million in the water of sulphate, chloride, and alkalies, the 
latter being commonly grouped under the name of sodium. Con- 
sideration of bicarbonate is precluded because estimates of it appar- 
ently were not made in the work on which the formulas are based. 
The three formulas represent the different relations between the 
alkali and the acid radicles. Under the first condition, with enough, 
or more than enough, chloride to satisfy sodium, it is assumed that 
chlorides other than that of sodium are as harmful as that compound. 
Cameron * found that magnesium chloride, sodium chloride, and cal- 
cium chloride had relative toxicities of 1.2: 1.0: 0.6, respectively, in 
the presence of an excess of calcium sulphate or of calcium sulphate 
and calcium carbonate. Under the second condition, where the 
chloride and sulphate radicles together are sufficient to satisfy sodium, 
and under the third, where both chloride and sulphate are insufficient 
to satisfy sodium, magnesium is assumed to have no deleterious effect. 
This base loses the greater part of its toxic power when much calcium 
is present and therefore this assumption seems justifiable as not only 
is calcium usually high in all soils, but also it commonly exceeds the 
proportion of magnesium in natural waters. Though the formulas 
are based on the relative predominance of the radicles, they should 
not be interpreted as signifying that the acids and bases are com- 
bined, but as presenting the maximum possibilities of the deposition 
of harmful alkali salts in the soil layer. Waters to which the first 
two formulas are applicable are likely to leave white alkali on evapo- 
ration, and those in the third class probably yield black alkali. 

i Cameron, F. K., and Breazeale, J. F., The toxic action of acids and salts on seedlings: Jour. Phys. 
Chemistry, vol. 8, p. 1, 1904. 



QUALITY OF WATER. 235 

The approximate amount of alkali in a water can be computed 
from the results of an assay by the following formula : 

Na = 0.83 CO3 + O.4I HCO 3 + 0.71 CI + 0.52 SO 4 -0.5 H. 

The symbols represent the amounts in parts per million of alkali 
(sodium and potassium) and the carbonate, bicarbonate, chloride, 
sulphate, and total hardness found by assay. The equation expresses 
the theoretical relation that the sum of the reacting values of the acid 
radicles minus the reacting values of calcium and magnesium, which 
together are one-fiftieth of total hardness, equals the reacting value 
of the alkalies; the factor 25 instead of 23, the atomic weight of 
sodium, is used for safety. Because of the approximate nature of 
the figures of assays, values of ~k computed from them should be 
reported with not more than two significant figures and to the nearest 
10 when they exceed 30. 

The following ratings for interpreting values of the alkali coeffi- 
cient are proposed by Stabler: 



Value of It (inches) . 






Good. 
Fair. 
Poor. 
Bad. 


6 to 18 


1. 2 to 5.9 







The value of Jc, showing the number of inches of water that would 
yield on evaporation sufficient alkali to inhibit the growth of very 
sensitive plants, indicates the relative degree of care that is essential 
in applying a water to irrigated tracts. As defined by Stabler, 
"good" waters are those that can be used for many years without 
special care to prevent alkali accumulation. Waters classed as "fair" 
require special care to prevent gradual concentration of alkali except 
in loose soils with free natural drainage. In using waters classed as 
"poor" care in selection of soils has been imperative and artificial 
drainage has frequently been necessary. The "bad" waters contain 
so much harmful matter in solution that they are practically valueless 
for irrigation. These ratings are based on general practice in the 
arid and semiarid regions of the United States, and so far as they can 
be checked by comparison with actual experience in the use of waters 
they answer all practical purposes. 

This rating, like any other that might be devised, should be liber- 
ally interpreted. It is well to repeat emphatically that it signifies 
only a comparison of the waters themselves on the basis of their 
mineral content. It has no reference whatever to the possibility of 
raising good crops on land to which the waters may be applied, 
because it does not take into account the alkali content and the tex- 



236 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

ture of the soil, drainage conditions, the method of irrigation, the 
duty of the water, or the other factors on which agricultural success 
depends. 

REMEDIES FOR ALKALI TROUBLES. 

WASHING DOWN THE ALKALI. 

The relation between applied water and soils makes it apparent 
that the farmer can control the alkali content of his ground to great 
extent by the manner in which he applies water and the care he takes 
to prevent accumulation of soluble salts near the surface. When a 
deep, readily pervious soil is covered with water to a proper depth 
by flooding, the water rapidly soaks into the soil, dissolving the 
alkali salts concentrated near the surface and carrying them down- 
ward beyond the zone of influence on the delicate feeding rootlets. 
But if the ground is not then protected against surface evaporation 
the water is drawn upward and alkali again impregnates the top 
layers. This action can be prevented in some measure by thorough 
cultivation as soon as possible after irrigation, and the shade afforded 
by trees and good stands of grass or grain also minimizes it. This 
shading effect partly explains why well-established growths of some 
cultures can thrive in soil containing an amount of alkali injurious 
to younger crops. A good stand of alfalfa, for instance, inhibits 
surface evaporation and consequent rise of alkali to the feeding roots, 
though the ground deeper down may contain enough alkali to kill 
the plants; whereas newly started alfalfa can not prevent evapora- 
tion, and the alkali, dissolved by the water and rising with it by 
capillarity, becomes concentrated where it can do the greatest 
damage. A shallow soil underlain by hardpan is not benefited by 
flooding alone, as the leaching is stopped by the impervious layer. 

It is a prevalent idea that alkali can be washed from a piece of 
land by flooding it with large quantities of water and then allowing 
the surplus to run off. The improvement is, however, not due so 
much to removal of the comparatively small quantities of material 
carried away in the off-flow as to depression of the alkali by the 
downward percolation just described. The results of some experi- 
ments by Headden * illustrate this well. Two waters, the compo- 
sition of which is given in columns A and B of Table 49, were used 
during two successive days to flood a tract of alkali land about 600 
feet long. Four samples of the off-flow were taken, two at the 
beginning of the off -flow and two just before the on-flow was stopped, 
and the average of the analyses of these four samples is given in 
column C. Though one of them, taken at the very commencement 
of the off -flow, carried 1,238 parts per million of dissolved solids, 
this high content lasted only a few minutes, and comparison of the 

i Headden, W. P., Colorado irrigation waters and their changes: Colorado Agr. Coll. Exper. Sta. Bull. 
82, 1903. 



QUALITY OF WATEK. 



237 



average with the results in columns A and B shows how little the 
total mineral content of the water that remained above ground and 
finally flowed off after crossing the entire area was increased by 
solution of the alkali in the soil. 

Table 49. — Effect of flooding on alkali as shown by composition of water. 
[Parts per million.] 



Constituents. 



Total solids 

Organic and volatile matter 

Silica (Si0 2 ) - 

Oxides of iron and aluminum (Fe 2 03+Al 2 03). 

Calcium (Ca) 

Magnesium (Mg) 

Manganese ( Mn) 

Sodium (Na ) 

Potassium (K) 

Carbonate radicle (C0 3 ) 

Sulphate radicle (SO4) 

Chloride radicle (CI) 



A 


B 


C 


D 


328 


706 


760 


1,415 


27 


37 


44 


92 


10 


14 


12 


23 


1.0 


3.4 


.8 


1.6 


43 


90 


93 


139 


10 


24 


30 


66 


.6 


.8 


.2 


.7 


42 


96 


102 


195 


3.6 


3.8 


5.6 


1.9 


64 


106 


112 


120 


113 


305 


335 


713 


10 


24 


24 


60 



3,278 
145 
20 

314' 

170 

1. 

436 

6. 

149 

1,885 
147 



A. Water used in irrigating on Sept. 1. 

B. Water used in irrigating on Sept. 2. 

C. Average composition of ofE-flow Sept. 2. 

D. Average composition of water from 4 shallow wells Aug. 31. 

E. Average composition of water from 4 shallow wells Sept. 2. 

Four shallow wells in the plot, protected against entrance of water 
over the top, were sampled before (column D) and after irrigation 
(column E). The composition of the ground water portrayed by 
these averages is typical in showing the downward passage of the 
alkali salts in the soil. The average amount of mineral matter in 
the off-flow is only slightly greater than that in the applied water 
that was used in greater quantity, but the water in the wells increased 
in dissolved solids from 1,415 parts to 3,278 parts per million, cal- 
cium, magnesium, sodium, sulphate, and chloride having been more 
than doubled. Headden estimates that the ground water gained 
about 5,000 pounds of mineral matter per acre-foot of water by this 
irrigation. 

The effect of natural precipitation in washing down the soluble 
salts can be illustrated by analyses of water from the same wells 
after a long period of heavy rainfall. Just before the rain stopped 
the water of one well contained 10,360 parts per million of total 
solids, an amount several times the normal; only eight days later 
solids Lad fallen to 6,450 parts; and to 2,030 parts after a month. 
This decided increase of mineral content after rainfall and the sub- 
sequent decrease coincident with the loss of water by evaporation 
and drainage can be explained by change in position of the soluble 
salts in the soil column. 

Irrigation by shallow furrows from which the water soaks into the 
ground causes downward transmission of alkali in pervious soils 
like flooding, with the added advantage that the decreased evapora- 



238 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

tion lessens the tendency toward surface concentration of alkali. 
Deep, narrow furrows would undoubtedly still further reduce the 
proportion of water lost by evaporation and would prevent the rise of 
alkali by affording deeper circulation of the water supply. 

DRAINAGE. 

Such downward washing of soluble substances affords no perma- 
nent relief, for the alkali, not being removed, may be drawn again 
to the surface, or may rise as a result of wasteful irrigation, a trouble 
common in water-logged soils. Downward washing can be safely 
relied on only when the soils are pervious and have good natural 
drainage. Application of heavily mineralized water even under 
such conditions year after year may increase the amount of the harm- 
ful ingredients and render them more difficult to handle. The recog- 
nized permanent remedy is installation of underdrains, through 
which the dissolved substances may be removed. The installation 
of drainage is costly, but it has become an essential part of irrigation 
systems wherever the soils are very bad or the waters are high in 
harmful ingredients, for it not only facilitates the removal of the 
deleterious salts originally in the ground but also affords means for 
preventing accumulation of alkali when very strong waters are used. 

The experimental plots cultivated by the Department of Agri- 
culture in Fresno County where the "rise of the alkali " has spoiled 
otherwise good ground have been thoroughly reclaimed by under- 
drainage. 1 The best results with strong saline waters have been 
obtained by irrigating copiously at frequent intervals. In con- 
junction with free drainage such operation prevents concentration of 
alkali salts in the soil, for any accumulation that may form is quickly 
dissolved and washed downward. 

MISCELLANEOUS REMEDIES. 






Though it is possible to remove a large proportion of the alkali 
crust by scraping the surface of the land that method is too expen- 
sive to be generally adopted. Growing and completely cropping 
plants that secrete relatively large quantities of alkali is tedious but 
fairly successful. The injurious effect of carbonate alkali can be 
greatly reduced by spreading the ground with gypsum, by action of 
which carbonate of lime and alkali sulphates are formed. As car- 
bonate alkalies are much more harmful than chlorides or sulphates 
treatment of this character lessens the toxic action. 

i Fortier, Samuel, and Cone, V. M., Drainage of irrigated lands in the San Joaquin Valley, Calif.: U. S. 
Dept. Agr. Exper. Sta. Bull. 217, 1909. 



QUALITY OF WATER. 239 

WATER FOR BOILER USE. 
FORMATION OF SCALE. 

The most common trouble in boilers is formation of scale, or 
deposition of mineral matter within the boiler shell. When water 
is heated under pressure and concentrated by evaporation, as in a 
boiler, certain substances are thrown out of solution and solidify on 
the flues and crown sheets or within the tubes. These deposits 
increase fuel consumption because they are poor conductors of heat 
and increase the cost of boiler repairs and attendance because they 
have to be removed. If the amount of scale is great or if it is allowed 
to accumulate the boiler capacity is decreased and disastrous explo- 
sions are likely to occur. 

The incrustation (scale) consists of the substances that are insoluble 
in the feed water or become so within the boiler under conditions of 
ordinary operation. It includes practically all the suspended matter, 
or mud; the silica, probably precipitated as the oxide (Si0 2 ); the 
iron and aluminum, appearing in the scale as oxides or hydrated 
oxides; the calcium, precipitated principally as carbonate and sul- 
phate; and the magnesium, found chiefly as oxide but also partly as 
carbonate. Scale is therefore a mixture, which varies in amount, 
density, hardness, and composition with the quality of water supply, 
the steam pressure, the type of boiler, and other conditions of use. 
Calcium and magnesium are the principal basic substances in the 
scale, over 90 per cent of which usually is calcium, magnesium, car- 
bonate, and sulphate. If much organic matter is present part of it 
is precipitated with the mineral scale, as the organic matter is decom- 
posed by heat or by reaction with other substances. If magnesium 
and sulphate are comparatively low or if suspended matter is com- 
paratively high the scale is soft and bulky and may be in the form of 
sludge that can be blown or washed from the boiler. On the other 
hand, a clear water relatively high in magnesium and sulphate may 
produce a hard, compact scale that is nearly as dense as porcelain, 
clings to the tubes, and offers great resistance to the transmission of 
heat. Therefore the value of a water for boiler use depends not only 
on the quantity but also on the physical structure of the scale pro- 
duced by it. 

CORROSION. 

Corrosion or "pitting" is caused chiefly by the solvent action of 
acids on the iron of the boiler. Free acids capable of dissolving iron 
occur in some natural waters, especially in the drainage from coal 
mines, which usually contains free sulphuric acid, and also in some 
factory wastes draining into streams. Many ground waters contain 
free hydrogen sulphide, a gas that readily attacks boilers, and some 



240 GROUND WATERS OF WESTERN SAN. DIEGO COUNTY, CALIF. 

contain dissolved oxygen and free carbon dioxide, which are also 
corrosive. Organic matter is probably a source of acids, for waters 
high in organic matter and low in calcium and magnesium are cor- 
rosive, though the nature and action of the organic bodies are not 
well understood, The chief corrosives are acids freed in the boiler by 
the deposition of hydrates of iron, aluminum, and magnesium, the 
last-named being the most important as it is the most abundant. 
The acid radicles that were in equilibrium with these bases may pass 
into equilibrium with other bases, displacing equivalent quantities 
of carbonate and bicarbonate; or they may decompose carbonates 
that have been precipitated as scale; or they may combine with the 
iron of the boiler, thus causing corrosion; or they may do all three, 
their action depending on the chemical composition of the water. 
Even with the most complete analyses this action can be predicted 
only as a probability. If the acid thus freed exceeds the amount 
required to decompose the carbonate and bicarbonate radicles it 
attacks the iron of the boiler and produces pits or tuberculations of 
the interior surface, leaks, particularly around rivets, and general 
deterioration. 

FOAMING. 

Foaming is rising of the water in the boiler and particularly in the 
steam space normally above the water, and it is intimately connected 
with priming, which is the passage from the boiler of water mixed 
with steam. Foaming results when anything prevents the free escape 
of steam from the water. It is usually ascribed to an excess of dis- 
solved matter that increases the surface tension of the liquid and 
thereby reduces the readiness with which the steam bubbles break. 
As sodium and potassium remain dissolved in the boiler water while 
the greater portion of the other bases is precipitated, the foaming 
tendency is commonly measured by the degree of concentration of 
the alkali salts in solution, because this figure in connection with 
the type of boiler determines to great extent the length of time that a 
boiler may run without danger of foaming. It is a fact that the 
worst foaming waters in railroad practice are encountered in the arid 
and semiarid regions of the Southwest where the quantity of dis- 
solved alkali is greatest. However, it is well known that suspended 
matter can cause foaming, for certain waters that deposit a moderate 
amount of scale but do not foam when clear, foam badly when they 
carry a great quantity of mud. Greth 1 states that foaming is due to 
condition of boiler, design of boiler, size and shape of water space, 
steam pipe, irregularity in blowing off, introduction of oil into the 
feed water from the exhaust steam, neglect to change water period- 
ically, irregularity of load, or improper firing and feeding. He con- 

1 Greth, J. C W., Water softening and purification for coal-mine operations (paper read before the West 
Virginia Coal Mining Institute, Bluefield, W. Va., June 7, 1910). 






QUALITY OF WATEE. 241 

eludes that it is not merely the presence of sodium salts in solution 
that causes foaming, but the presence of other substances which 
together with the sodium salts and operating conditions bring about 
foaming. It is believed that a strong solution of sodium car- 
bonate might not induce excessive foaming in water otherwise pure, 
but its introduction into a boiler, which under operating conditions 
invariably contains suspended matter or precipitated sludge, might 
produce foaming by increasing the suspended matter either by pre- 
cipitating calcium and magnesium or by loosening previously depos- 
ited scale. Under working conditions it is difficult to distinguish the 
actual cause of the trouble. Experience has shown that the type of 
boiler, steam pressure, and other operating conditions may greatly 
accelerate or retard foaming. 

REMEDIES FOR BOILER TROUBLES. 

The best way of remedying unsatisfactory boiler supplies is to 
treat them before they enter boilers, but where this is impracticable 
trouble can be minimized in various ways. Low-pressure large-flue 
boilers are used in many stationary plants with hard waters, and it 
is said that the scale formed in them is softer and more flocculent and 
can therefore be more readily removed than that formed in high- 
pressure boilers. Blowing off is about the only practical means of 
preventing foaming, because this trouble is due principally to con- 
centration of substances in the residual water of the boilers. Accu- 
mulated sludge, or soft scale, is removed by blowing, particularly in 
locomotive practice. In condensing systems much of the trouble due 
to mineral matter in the feed water is obviated because the quantity 
of raw water supplied is proportionately small. Yet the problem is 
not completely solved in such systems, because the incrusting or 
corrosive action is transferred from the boiler to the condenser, which 
requires more or less cleaning and repairing in proportion to the 
undesirable qualities of the water supply. 

BOILER COMPOUNDS. 

Boiler compounds are widely used in regions where hard waters 
abound, but treatment within the boiler should be given only when it 
is impossible to purify the supply beforehand or when the supply is 
relatively pure and requires only minor correction. If previous puri- 
fication is not practicable some feed waters can be improved by judi- 
cious addition of chemicals. Many substances, ranging from flour, 
oatmeal, and sliced potatoes to barium and chromium salts, have 
been recommended for such use, but only a few have proved to be 
really efficient. These substances have been classified 1 according to 
their action within the boiler. Those that attack chemically the 

1 Gary, A. A., The use of boiler compounds: Am. Machinist, vol. 22, pt. 2, p. 1153, 1899. 
115536°— 19— wsp 446 16 



242 

scaling and corroding constituents precipitate incrusting matter and 
neutralize acids. Soda ash, the commercial form of sodium carbonate 
containing about 95 per cent Na 2 C0 3 , is the most valauble substance 
of this character, because it is cheap and its use is attended with the 
least objectionable results. Tannin and tannin compounds are also 
used for the same purpose. The addition of limewater to the feed 
to prevent corrosion and to obviate foaming has been recommended, 1 
and it is probable that it would improve waters high in organic 
matter and very low in incrustants. Such practice increases the 
incrustants in proportion to lime added but prevents corrosion. 
Soda ash neutralizes free acids, precipitates the incrusting ingredients 
as a softer, more nocculent material, which is more easily removed 
from the boiler, and increases the foaming tendency of the water by 
increasing its content of dissolved matter. The proper amount to 
be used depends on the chemical composition of the water and the 
style of the boiler. 

The second class of boiler compounds comprises those that act 
mechanically on the precipitated crystals of scale-making matter 
soon after they are formed, surrounding them and robbing them of 
their cement-like action. Glutinous, starchy, and oily substances 
belong to this class, but they are not now used to any considerable 
extent because they thicken and foul the water more than they pre- 
vent the formation of hard scale. 

The third class comprises compounds that act mechanically like 
those of the second class and also partly dissolve deposited scale, 
thus loosening it and aiding in its ready removal. Of these, kerosene 
is very effective, but graphite is believed to be still better. 

Many boiler compounds possessing or supposed to possess one or 
more of the functions just described are on the market and are widely 
sold. Some are effective and some are positively injurious. Most 
of them depend for their chief action on soda ash, petroleum, or a 
vegetable extract, but all are costly compared with lime and soda ash. 
Boiler compounds can not reduce the amount of scale and may 
increase it. Their only legitimate functions are to prevent corrosion 
and deposition of hard scale and to remove accumulations of scale 
that have become attached to the boiler. Every engineer should bear 
in mind that steam boilers are costly and that fuel and boiler repairs 
are costly and should hesitate to add substances to his feed water 
without competent advice as to their effect. It is far more economical 
to have the water supply analyzed and to treat it effectively by well- 
known chemicals in proper proportion, either within or without the 
boiler, than to experiment with compounds of unknown composition. 

i Palmer, Chase, Quality of the underground waters in the Blue Grass region of Kentucky: U. S. Geol. 
Survey Water-Supply Paper 233, p. 187, 1909. 



QUALITY OF WATER. 243 

NUMERICAL STANDARDS. 

Stabler's excellent mathematical discussion of the quality of waters 
with reference to industrial uses 1 contains several formulas by which 
the effect of waters may be computed. They have been recalculated 
in order to obtain the estimates in parts per million. The terms in- 
volving iron, aluminum, and free acids have been omitted because 
these substances are too scarce to call for consideration in such 
approximate rating; and the terms involving sodium and potassium 
have been united for simplicity. 

(1) s = Sm + Cm + 2.95Ca+1.66Mg 

(2) h = Si0 2 + 1.66 Mg+1.92 Cl+1.42 S0 4 -2.95 Na 

(3) f = 2.7Na 

(4) c = 0.0821 Mg-0.0333 CO 3 -0.0164 HC0 3 . 

These equations express numerically some of the relations that have 
been discussed in the preceding sections on scale, corrosion, and 
foaming. Sm, Cm, Si0 2 , Ca, Mg, Na, CI, S0 4 , C0 3 , and HC0 3 repre- 
sent the amounts in parts per million, respectively, of suspended 
matter, colloidal matter (oxides of silicon, iron, and aluminum), silica, 
calcium, magnesium, alkalies, chloride, sulphate, carbonate, and 
bicarbonate. 

Formula 1 gives the amount of scale (s) that would probably be 
formed from the water under ordinary conditions of boiler operation; 
as the ground waters of San Diego County are practically clear, Sm 
is equal to zero. Where not determined Cm has been given a value 
of 34, for waters, the average of Si0 2 in 50 analyses of ground waters 
in San Diego County. 

Formula 2 gives the amount of hard scale forming ingredients (h) . 

The ratio - expresses the relative hardness of the scale. If - is 

greater than 0.5 the scale may properly be called hard; if it is less 
than 0.25 the scale may properly be called soft. 

Scale (s) has been estimated from the data of the assays by adding 
to total hardness (H) the value of Cm used in formula 1 (s = Cm + 
H). (See formula 1 for value of Cm used in assays for San Diego 
County.) As H theoretically equals 2.5 Ca+4.1 Mg, and the last 
two terms of equation 1 are 2.95 Ca + 1.66 Mg, the unknown but 
variable ratio between calcium and magnesium introduces an uncer- 
tain error. Estimates of the scale-forming constituents are, however, 
always approximate, and experience indicates that this computed 
value is accurate enough for relative ratings. 

Formula 3 gives the amount of the foaming ingredients (f), as esti- 
mated from the probable content of alkali salts. The value of sodium 

1 Stabler, Herman, Some stream waters of the western United States, with chapters on sediment carried 
by the Rio Grande and the industrial application of water analyses: U. S. Geol. Survey Water-Supply 
Paper 274, p. 165, 1911. See also Eng. News, vol. 60, p. 355, 1908.. 



244 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

(Na) computed by the formula on page 235 has been used in computing 
the amount of the foaming ingredients from the results of the assays. 

Formula 4 has been used to calculate the corrosive tendency of 
the water (c). As can be readily seen from the coefficients, it 
expresses the relation between the reacting values of magnesium and 
the radicles involving carbonic acid (p. 228) . If c is positive, the water 
is corrosive. If c + 0.0499 Ca, the reacting value of calcium, is nega- 
tive, the mineral constituents will not cause corrosion, but whether 
organic matter or electrolysis will cause it is uncertain. If c + 0.0499 
Ca is positive corrosion is uncertain. These conditions of reaction 
may be restated to conform to the data of the assays thus: If 0.033 
C0 3 + 0.016 HCO3 equals or exceeds 0.02 H the mineral constituents 
will not cause corrosion. If 0.004 H exceeds 0.033 C0 3 + 0.016 
HCO3 the water is corrosive. One-fiftieth of the total hardness 
(0.02 H) is equivalent to the reacting value of calcium and magnesium, 
and H divided by 230 (0.004 H) is equivalent to the reacting value of 
magnesium on the assumption that Ca = 6 Mg, a ratio in which 
magnesium is given its smallest probable value in relation to calcium. 
The reacting values of carbonate and bicarbonate are represented, 
respectively, by 0.033 C0 3 and 0.016 HC0 3 , the coefficients of which 
are obtained by dividing the valence of each radicle by its molecular 
weight. 

After these three attributes of boiler feed have been computed 
rating the water is largely a matter of judgment based on experi- 
ence. The committee on water service of the American Railway 
Engineering and Maintenance of Way Association has offered two 
classifications by which waters in their raw state may be approxi- 
mately rated, but, as the report states, "it is difficult to define by 
analysis sharply the line between good and bad water for steam- 
making purposes." Table 50 gives these classifications with the 
amounts transformed to parts per million. 

Table 50. — Ratines of waters for boiler use according to proportions of incrusting, 
corroding, and foaming constituents. 



Incrusting and corroding constitu- 
ents. 


Foaming constituents. 


Parts per million. 


Classification.a 


Parts per million. 


Classification^ 


More 
than— 


Not more 
than— 


More 
than— 


Not more 
than — 




90 
200 
430 


Good. 
Fair. 
Poor. 
Bad. 




150 
250 
400 


Good. 
Fair. 
Bad. 
Very bad. 


90 
200 
430 


150 
250 
400 







a Am. Ry. Eng. and Maintenance of Way Assoc. Proc, vol. 5, p. 595. 1904. 
b Idem, vol. 9, p. 134, 1908. 



QUALITY OF WATER. 245 

The quantity of foaming ingredients (f ) should always be considered 
in conjunction with the probable amount of scale or sludge that would 
be formed, the hardness of the scale, and the tendency toward corro- 
sion. These ratings result in a classification rather more rigid than 
that usually reported by chemists of railroads in California, and for 
that reason those who are thoroughly familiar with local conditions 
and with the chemistry of water will doubtless prefer to disregard 
the descriptive terms of the classification and to draw their own con- 
clusions regarding the quality of the waters from the figures repre- 
senting scaling, foaming, and corrosion. The classifications are 
given principally for the aid of those not thoroughly familiar with 
such matters, and rather to indicate the limits of usefulness than to 
define rigidly the value of the waters. 

No matter how low a water may be in undesirable constituents 
it is poor economy to use it if it is much poorer in quality than the 
average water of the region in which it occurs. On the other hand, 
if the best available supply is poor the economy of purifying it even 
at large expense is obvious. Along the Atlantic coast, where waters 
containing less than 100 parts per million of incrusting ingredients are 
extremely common, a supply carrying 200 parts of such substances 
would not be considered fair for boiler use. Throughout most of 
Mississippi Valley, however, such a supply would be considered good, 
because in that region natural waters not exceeding 100 parts in scale- 
forming constituents are rare. This variance in local standards is 
well illustrated by the opinions on the two sides of San Joaquin 
Valley as to what constitutes a good boiler water, and because of 
it numerical standards should be interpreted relatively, not literally. 
At the same time any classification by nominal ratings must be 
applied absolutely if the terms are to have comparative significance 
outside the region where the waters exist. Waters of poor quality 
can be improved by treatment in softening plants. How bad a 
water may be used without treatment depends on the cost of softening 
the water and the relative saving effected by the use of the softened 
water. A'report * of the committee on water service of the American 
Railway Engineering and Maintenance of Way Association sets forth 
the factors involved. The benefits include the saving in boiler 
cleaning, repairs, and fuel, the decrease in the time during which 
the boilers must be withdrawn from service for cleaning and repairs, 
the decreased depreciation of the boilers, and the value of the 
materials removed by softening. The cost of softening includes the 
cost of labor and power for the softening apparatus, the cost of soften- 
ing chemicals, the interest on the cost of installation, depreciation in 
the value of the softening plant, and the waste in changing boiler 
feed due to increased foaming tendency. 

1 Am. Ry. Eng. and Maintenance of Way Assoc. Proc, vol. 8, p. 601, 1907. 



246 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

In locomotive service it is in general economical to treat waters 
containing 250 to 850 parts per million of incrustants and to treat 
those containing less than 250 parts if the scale formed contains much 
sulphate. 1 As the incrusting solids may commonly be reduced to 
80 or 90 parts per million, the economy of treating boiler waters 
deserves consideration in a region where many supplies contain 300 
to 500 parts per million of incrusting matter. 

The amount of mineral matter that makes a water unfit for boiler 
use depends on the combined effect in boilers of the softening reagents 
used with such waters and of the constituents not removed by soften- 
ing. Sodium salts added to remove incrustants or to prevent corro- 
sion increase the foaming tendency, and this increase may be great 
enough to render a water useless for steaming. It is not of much 
benefit to soften a water containing more than 850 parts per million 
of nonincrusting material and much incrusting sulphate. 1 Trouble 
from priming in locomotive boilers begins at a concentration of about 
1,700 parts per million of foaming constituents, and the limit of 
safety for stationary boilers is reached at a concentration of about 
7,000 parts. Though waters containing as high as 1,700 parts per 
million of foaming constituents have been used, it is usually more 
economical to incur considerable expense in replacing such supplies 
by better ones. 

WATER FOR MISCELLANEOUS INDUSTRIAL USES. 
GENERAL REQUISITES. 

Many articles are affected by the ingredients of the water used in 
their manufacture and can be improved by its purification. If by 
the same process the boiler efficiency of the factory can be increased 
the expense is often justified when it would not be warranted merely 
by the increased value of the product. This observation applies 
particularly to paper, pulp, and strawboard mills, laundries, and 
other establishments where large quantities of water are evaporated 
to furnish steam for drying, and to ice factories and similar plants 
where distilled water is required. 

Besides its use for steam making water plays a specific part in 
many manufacturing processes. In paper mills, strawboard mills, 
bleacheries, dye works, canning factories, pickle factories, cream- 
eries, slaughterhouses, packing houses, nitroglycerin factories, distil- 
leries, breweries, woolen mills, starch works, sugar works, canneries, 
glue factories, soap factories, and chemical works water becomes a 
part of the product or is essential in its manufacture. In most of 
these establishments the principal function of the water is that of a 
cleansing agent or a vehicle for other substances, and therefore a 
supply free from color, odor, suspended matter, microscopic organisms 

1 Am. Ry. En*, and Maintenance of Way Assoc. Proc, vol. 6, p. 610, 1905. 



QUALITY OF WATER. 247 

and especially from bateria of fecal origin, and fairly low in dissolved 
substances, especially iron, is with few exceptions satisfactory. 
But water hygienically acceptable is necessary where it comes into 
contact with or forms part of food materials, as in the making of 
beverages, sugar, and dairy or meat products. As ideal waters for 
any use are rare, the manufacturer must ascertain what degree of 
freedom from impurities is necessary to prevent injury to his ma- 
chinery or to his output and whether the cost of obtaining such 
purity is counterbalanced by decreased cost of production and 
increased value of product. 

EFFECTS OF DISSOLVED AND SUSPENDED MATERIALS. 

The effects in some industries of the substances most commonly 
found in water are outlined in the following pages, the object being 
to offer approximate standards for classification. 

FREE ACIDS. 

Free mineral acids, such as the sulphuric acid in drainage from 
coal mines or the hydrochloric acid in the effluents of some industrial 
establishments, are especially injurious and nearly always have to 
be neutralized before the waters containing them can be used in- 
dustrially. In paper mills, cotton mills, bleacheries, and dye works 
waters containing a measureable amount of free mineral acid de- 
compose chemicals, streak and rot fabrics, and corrode and rapidly 
destroy metal screens, strainers, and pipes. 

SUSPENDED MATTER. 

Suspended matter in surface waters may be of vegetable, mineral, 
or animal origin, as it consists of particles of sewage, bits of leaves, 
sticks and sawdust, and sand and clay. The fine silt so common in 
rivers of the West is largely derived from clay. Few well waters 
contain suspended animal or vegetable matter, but many carry finely 
divided sand and clay, and many become turbid by precipitation of 
dissolved ingredients. Suspended matter is objectionable in all 
processes in which water is used for washing or comes into contact 
with food materials, because it is likely to stain or spot the product. 
Suspended matter due to precipitated iron is especially injurious even 
in small amount. Suspended vegetable or animal matter liable to 
decomposition or to partial solution is much more objectionable, even 
in small amount (10 to 20 parts per million), than equal quantities of 
mineral matter. For these reasons water should be freed from sus- 
pended matter before being used for laundering, bleaching, wool 
scouring, paper making, dyeing, starch and sugar making, brewing, 
distilling, and similar processes, in making the coarser grades of 
paper, such as strawboard, a small amount of suspended matter is 
not especially injurious, but for the finer white and colored varieties 
clear water is essential. 



248 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

COLOR. 

Color in water is due principally to solution of vegetable matter. 
Materials bleached, washed, or dyed light shades in colored water are 
likely to become tinged. Highly colored waters can be used in 
making wrapping or dark- tin ted papers but not in making the white 
grades, and paper manufacturers are put to great expense for water 
purification on that account. The lower waters are in color, there- 
fore, the more desirable they are for use in bleacheries, dye works, 
paper mills, and other factories where brown tints in the products 
are undesirable. 

IRON. 

Iron is the most undesirable dissolved constituent, and its presence 
in comparatively small quantities necessitates purification. Many 
ground waters contain 1 to 20 parts per million of iron, which may 
be precipitated by exposure to the air and by release of hydrostatic 
pressure, causing the waters to become turbid, and many such waters 
develop rusty-looking gelatinous growths that may interfere in in- 
dustrial operations. In all cleansing processes, especially if soap or 
alkali is used, precipitated iron is likely to cause rusty or dull spots. 
In contact with materials containing tannin compounds iron forms 
greenish or black substances that discolor the product. Therefore 
many waters containing amounts even as small as 1 or 2 parts per 
million of iron have to be purified before they can be used industrially. 
In water for dye works iron is especially objectionable and commonly 
prevents the use of the water without purification. 1 Iron in the 
water supply of paper mills may be precipitated on the pulp, giving 
a brown color, or during sizing or tinting, giving spotty effects. 
Water containing much iron can not be used in bleaching fabrics 
because salts that spot the goods are formed. The dark-colored com- 
pounds that iron forms with tannin discolor hides in tanning. 

CALCIUM AND MAGNESIUM. 

Calcium and magnesium are similar in their industrial effects. In 
water their amounts bear a more or less definite relation to each other, 
most waters carrying 10 to 50 per cent as much magnesium as calcium. 
Both are precipitated on whatever is boiled in water containing them, 
forming a deposit that may interfere with later operations. They 
also decompose equivalent amounts of many chemicals employed in 
technical operations, causing waste and forming alkaline-earth com- 
pounds that interfere with the later treatment of fabrics. These are 
the strongest incentives to preliminary softening. Some of the chem- 
icals used to disintegrate the fibers in making pulp are consumed by 
the calcium and magnesium in the water supply, though the loss from 
this source is not nearly so great as that which occurs later when the 



* Sadtler, S. P., A handbook of industrial organic chemistry, p. 483, Philadelphia, 1900. 



I 



QUALITY OF WATER. 249 

resin soap used in sizing the paper is decomposed by the calcium and 
magnesium. The insoluble soaps thus created do not fix themselves 
on the fibers, but form clots and streaks. Similar decomposition of 
valuable cleansing materials and subsequent deposition of insoluble 
compounds take place in laundering, wool scouring, and similar proc- 
esses. In the manufacture of soap, calcium and magnesium form 
with the fatty acids curdy precipitates that are insoluble in water and 
therefore have no cleansing value. They interfere with many dyeing 
operations, neutralizing chemicals and changing the reactions of the 
baths, besides forming insoluble compounds with many dyes. Very 
soft water, on the other hand, is said to be undesirable in paper mills 
for loading papers with any form of calcium sulphate because such 
waters dissolve part of the loading materials. 1 Probably waters high 
in chlorides would also be bad for this purpose, because chlorides 
increase the solubility of calcium sulphate. 

CARBONATE. 

The effects of carbonate and bicarbonate in waters used in industrial 
processes are commonly not differentiated. It is not unusual to 
estimate the combined carbonic acid and to state it as the carbonate 
without distinguishing between carbonate and bicarbonate, though 
in many natural waters the carbonate radicle is absent and the com- 
bined carbonic acid is in the form of bicarbonate. If hard waters 
proportionately high in carbonate and low in sulphate are boiled, the 
bicarbonate radicle is decomposed, free carbonic acid is given off, 
and the greater part of the calcium and magnesium is precipitated. 
Consequently waters of that character are generally more desirable 
for industrial operations than waters high in sulphate and low in car- 
bonate, whose hardening cons titu tents are not greatly reduced by 
boiling. 

SULPHATE. 

Hard waters with sulphate predominating are desirable in tanning 
heavy hides, because they swell the skins, exposing more surface for 
the action of the tan liquors. 2 Sulphate interferes with crystallization 
in sugar making by increasing the amount of sugar retained in the 
mother liquor. 

CHLORIDE. 

High chloride is usually accompanied by high alkalies. Appreci- 
able amounts of chloride are injurious in many industrial processes. 
Beverages and food products, of course, can not be treated with 
waters very high in chloride without becoming salty. In tanning, 
chloride causes the hides to become thin and flabby. 2 Animal char- 
coal used in clarifying sugar is robbed of its bleaching power by 

1 Cross, C. F., and Bevan, E. J., A textbook of paper making, p. 294, New York, 1900. 

2 Parker, H. N., and others, The Potomac River basin: U. S. Geol. Survey Water-Supply Paper 192, 
p. 194, 1907. 



250 

absorption of salt. The quality of sugars is affected by chloride- 
bearing waters, because saline salts are incorporated in the crystals. 1 
The only commercially developed way of removing chloride from 
water is distillation. As the cost of this process has been greatly 
reduced by use of multiple-effect evaporators, it is worth considera- 
tion where chloride-bearing waters must be used. 

ORGANIC MATTER. 

Organic matter of fecal origin is, of course, dangerous in any water 
that comes into contact with food products, and water so polluted 
should be purified before being used. Care in this respect is par- 
ticularly necessary in creameries, slaughterhouses, canneries, pickle 
factories, and sugar factories. Organic matter not necessarily capa- 
ble of producing disease is further undesirable in industrial supplies 
because it induces decomposition in other organic materials, like 
cloth, yarn, sugar, starch, meat, or paper, rotting and discoloring 
them, and because it causes slime spots on fabrics by supporting algae 
growths. 

HYDROGEN SULPHIDE. 

Hydrogen sulphide (H 2 S), a gas with an odor like that of rotten 
eggs, occurs dissolved in some ground waters. It is corrosive even 
in small quantities, and it also injures materials by discoloring and 
rotting them. 

MISCELLANEOUS SUBSTANCES. 

Silica and aluminum are usually not present in sufficient quantity 
appreciably to affect any industrial process, except those in which 
water is evaporated. Large quantities of sodium and potassium, by 
adding to the amount of dissolved matter, are objectionable in some 
manufacturing operations. Phosphates, nitrates, and some other 
substances not noted in this outline interfere with industrial chemical 
reactions, but they are present in few natural waters in sufficient 
quantity to have noticeable effect. 

QUALITY IN RELATION TO GEOLOGIC SOURCE. 
GENERAL RELATIONS. 

The wells in the part of San Diego County covered by this paper 
derive their supplies from (1) pre-Cretaceous crystalline rocks and 
the residuum resulting from their decomposition, (2) Tertiary and 
older sedimentary formations, and (3) Quaternary valley fill. Of 
the 121 samples of ground water that were analyzed or assayed, 17 
were derived from the residuum, 26 from Tertiary or older sedimen- 
tary formations, and 78 from valley fill. (See pp. 251-258 and Table 
46, opposite p. 222.) 

Table 51 shows the range in total dissolved solids and the average 
content of dissolved solids in the samples analyzed from each of the 

i Dela Coux, M. A. J., L'eau dans l'industrie, p. 152, Paris, 1900. 



QUALITY OF WATER. 251 

three geologic divisions. Only analyses of samples from wells sup- 
plying water are included in the results given in Tables 51 and 54 
and in the discussion following, samples from oil wells (F7, K16, and 
K37) being excluded. Analyses of water from wells F7, K16, and 
K37 are given in Table 57, pages 260-261. 

Table 51. — Comparison of quantities of total dissolved solids a in waters analyzed from 

different geologic sources. 



Geologic source. 



Number 
of sam- 
ples.. 



Total dissolved solids 
in parts per million. 



Range. Average 



Residuum 

Tertiary and older sediments . 
Valley fill 



392-2,552 
274-3,409 
320-5,060 



1,125 
1,183 
1,516 



a Taken from analyses published in this report. 

The table shows a wide range in mineral content in the waters 
within each of the three groups and the average mineral content in 
all of them is rather high. As the formations differ from each other 
both in origin and in composition, it might reasonably be expected 
that the waters obtained from them would show considerable differ- 
ences in quality, but the differences are not very marked. 

The similarity between the waters from the different geologic 
sources is evident also when the quantities of different chemical con- 
stituents are compared; and they are, moreover, similar in that they 
show about equally wide range in chemical composition. Of the 47 
well waters analyzed 43 are of the sodium-chloride type, 3 are calcium- 
carbonate, and 1 is sodium-carbonate. The average chloride con- 
tent of all the 47 waters analysed is 496 parts per million, the average 
for waters from valley fill being 566 parts, for waters from Tertiary 
and older sediments 450 parts, and for waters from residuum 304 
parts per million. 

The analyses of ground waters from this area, as given in Table 
57, pages 260-261, show so wide a range in chemical composition, 
regardless of location or geologic source, that it is not possible accurately 
to predict the quality of a water that may be found in any part of 
the area. However, rather highly mineralized sodium-chloride 
waters, fairly satisfactory for use for domestic supplies and for irri- 
gation, and very bad for use in boilers, are greatly predominant in 
San Diego County and may be regarded as typical for the area. 

WATER FROM RESIDUUM. 

The residuum of the highland basins, as described on page 71, 
is derived mainly from coarse granitic rocks by the chemical alter- 
ation of some of their mineral components and by the solution and 
removal of some chemical constituents by percolating water. During 



252 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



the early stages of rock decomposition the only apparent change 
consists of a granulation of the surficial parts of a formation whereby, 
instead of a dense, hard rock, there remains a disintegrated mass that 
crumbles at a touch of the hand and yields readily to excavation by 
means of a pick and shovel. The pore spaces are enlarged and the 
water-bearing capacity of the rock is greatly increased by decom- 
position, so that where topographic conditions are favorable and dis- 
integration extends to a considerable depth, material of this kind 
may be an important source of ground water. The residuum in 
many of the highland valleys is favorably situated, and the disinte- 
gration reaches depths of as much as 100 feet, and in many places 
the formation yields sufficient water for the irrigation of farm lands. 

The chemical quality of the water in residuum is determined by 
the solubility of the mineral substances in the residuum and the 
length of time that the waters remain in contact with these sub- 
stances, except where the residuum has been contaminated by sea 
water, by highly mineralized surface water, or by water issuing from 
sedimentary deposits that contain much soluble mineral. The waters 
in the residuum take mineral matter into solution very slowly, and, 
except where they have been contaminated from other sources, they 
may be expected to contain only small quantities of dissolved solids. 
There are probably many places in San Diego County at which waters 
of low mineral content may be obtained from residuum, but only 
two samples were collected for analysis during this investigation. 

Analyses of these two samples, which are believed to fairly repre- 
sent the quality of water in uncontaminated residuum, and their 
classification for use as domestic supplies for irrigation or in boile 
are given in Table 52. 

Table 52. — Partial analyses and classification of two samples of water from uncon- 
taminated residuum. 

[Parts per million. S. C. Dinsmore, analyst. Numbers at head of columns refer to corresponding num- 
bers on Plate II.] 



dr 



Clo 



II 18 6 



Silica(Si0 2 ) 

Iron(Fe) 

Calcium (Ca) 

Magnesium (Mg) 

Sodium and potassium (Na+ K) < 

Carbonate radicle (C0 3 ) 

Bicarbonate radicle (HC0 3 ) 

Sulphate radicle ( S0 4 ) 

Chloride radicle (CI) 

Nitrate radicle (N0 3 ) 

Total dissolved solids at 180* C. . 



Total hardness as CaC0 3 c 

Chemical character 

Quality for domestic use . 

Quality for irrigation 

Quality for boiler use 

Date of collection (1914) . . 



47 



.03 



62 


38 


28 


26 


15 


87 


.0 


.0 


229 


171 


14 


13 


66 


157 


10 


19 


392 


490 


270 


202 


Ca-C0 3 . 


Na-Cl. 


Fair. 


Good. 


Good. 


Fair. 


Poor. 


Fair. 


Nov. 21. 


Nov. 24. 



a Dug well 65 feet deep on Red Mountain ranch, 3 miles east of Fallbrook, in SW. \ sec. 15, T. 9 S., 
R.3W.; see also corresponding number in Table 46, opposite p. 222. 

& Drilled well 74 feet deep, of Nick Anderson, in Santa Maria Valley, about U miles south of Ramona 
post office; see also corresponding number in Table 46, opposite p. 222. 

c Calculated. 



QUALITY OF WATER. 253 

These samples do not afford conclusive evidence of the quality of 
water in the residuum of the highland area, but they are at least 
consistent with the belief that such waters generally contain only 
small or moderate quantities of dissolved mineral matter; and in the 
absence of more information it is reasonable to expect that wells in 
highland valleys underlain by residuum or decomposed granite will 
furnish water of good quality, similar to the samples described above, 
provided no highly mineralized water passes into the residuum from 
deposits of valley fill or other sources, a possibility indicated by the 
results of analyses of water from residuum in highland basins. 

Waters that have circulated through valley fill or the older sedi- 
mentary formations of this area are generally highly mineralized, 
but it is also probable that some residuum waters may owe their 
high mineral content to prolonged contact with mineral substances 
of the residuum itself. The residuum is almost as porous as valley 
fill, and it is more porous than most of the Tertiary sediments, so 
that the amount of surface presented to the solvent action of per- 
colating, water is very great. The movement of ground water is 
generally slow, even under most favorable conditions, and in the 
flat-floored basins of the highland area it is in some places hardly 
appreciable. In such places ground water may remain in contact 
with the rock particles long enough to permit the solution of consid- 
erable quantities of mineral . matter. So far as this investigation 
has shown, long contact is the only reasonable explanation of the 
presence of mineral substances in solution in waters from the resid- 
uum where they are obviously not contaminated by seepage from 
' sedimentary formations; it is certainly responsible in some measure 
for the quality of residuum waters, whether there is seepage from 
sediments or not. It is possible that the high mineralization of 
some of the waters from residuum in this county is also due to pro- 
longed contact. 

WATER FROM THE TERTIARY AND OLDER SEDIMENTARY FORMATIONS. 

Most of the Tertiary and underlying Cretaceous formations that 
are penetrated by wells in the western part of San Diego County 
were deposited in sea water, and as shown by the record of the 
Balboa oil well (see p. 55), which penetrated sedimentary forma- 
tions to a depth more than a mile below sea level, most of the 
beds, at least nine-tenths of the known section, still lie below sea 

! level. Moreover some of the beds that now lie above the level of 
the sea have been submerged in Quaternary time. It is to be ex- 

! pected, therefore, that waters derived from the beds which still lie 
below sea level and from those above sea level that are most resistant 
to the leaching action of percolating water will yield waters contain- 
ing large quantities of mineral matter. 



254 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

In addition to mineral substances derived from sea water, there 
are the soluble salts contained in the materials that make up the 
formations. Where shales and sandstones, especially those of the 
San Diego formation, are exposed in section they are commonly 
coated with a white efflorescence due to leaching and deposition by 
water that percolates through the beds and evaporates on the exposed 
surfaces. These coatings are concrete evidences of readily soluble 
mineral matter in the deposits and explain the high mineral content 
of waters derived from them. 

Partial analyses were made of 20 samples from wells that draw 
their supplies from Tertiary and older sedimentary formations. The 
results (excluding analyses from oil wells, F 7, K 16, and K37) show a 
high average concentration, 1,183 parts per million of total dissolved 
solids. There is a very wide range in quantities of total dissolved 
solids, from 283 to 3,409 parts per million, and there are correspond- 
ingly wide ranges in the quantities of the different mineral constit- 
uents, so that it is not practicable to indicate a water that would 
typically represent Tertiary supplies (see Table 54). The quality 
does not vary consistently with depth or location but depends on 
local stratigraphic conditions at individual wells. As, however, most 
of the waters already obtained from this source are highly' mineralized 
sodium-chloride waters, fair or poor for domestic use, poor for irriga- 
tion, and very bad for boilers, water of this type may in general be 
expected from new wells. 

Most of the wells that draw their supplies from Tertiary beds are 
on terraces where the soil is heavy and much less pervious than the 
soils in areas underlain by valley fill. These soils are not naturally 
well drained and it is not probable therefore that waters classified as 
poor for irrigation can be successfully applied on them unless ade- 
quate means are provided for artificial soil drainage. 

Of the 17 water- well samples analyzed from Tertiary beds 10 were 
classified as poor for irrigation, 6 as fair and 1 as good. It is a matter 
of interest that the sample classified as good for irrigation was obtained 
from a well (K 30) that had been drilled especially to provide water 
for irrigation, and that although this water comes from a stratum 
620 feet below the surface, nearly 1,000 feet below the top of the 
San Diego formation, it is one of the least mineralized waters obtained 
in the county. The contrast between this water and the water 
obtained from the Balboa oil well (K 37), which at present draws 
its supply from different horizons between the depths of 900 and 5,000 
feet, is shown in the following table: 






QUALITY OF WATER. 



255 



Table 53. — Partial analyses and classification of waters of extreme types from Tertiary 

deposits. 

[Parts per million.] 



Silica (SiOj) 

Iron(Fe) 

Calcium (Ca) 

Magnesium (Mg) 

Sodium and potassium (Na+K)d . 

Carbonate radicle (C0 3 ) 

Bicarbonate radicle (HC0 3 ) 

Sulphate radicle (SO4) 

Chloride radicle (CI) 

Nitrate radicle (N0 3 ) 

Total dissolved solids at 180° C. . . 



Total hardness as CaC0 3 d . 

Chemical character 

Quality for domestic use . . 

Quality for irrigation 

Quality for boiler use 



Date of collection. 
Analyst 



K 30. « & 




Mar. 16, 1918 

Alfred A. Cham- 
bers and C. H. 
Kidwell. 



K 37. « c 



44 
Tr. 
550 

27 

2,565 

26* 
1,381 
3,965 

8,764* 



.0 



.00 



1,490 
Na-Cl. 
Unfit. 
Bad. 
Very bad. 

June 9, 1915. 
S. C. Dinsmore. 



a Number on Plate II. 

6 Drilled well of Roger Topp, Ex Mission San Diego, Murphy Canyon, Calif ; see also corresponding 
number in Table 46, opposite p. 222. 

c Oil well of Balboa Oil Co., Pueblo Lands of San Diego, Calif.; see also corresponding number in Table 
46, opposite p. 222. 

d Calculated. 

Waters as good as that from well K 30 probably can not be com- 
monly expected from this source, and, on the other hand, waters as 
bad as that from well K 37 are not likely to be encountered in many 
wells. Table 54 presents the averages of analyses of Tertiary waters. 



Table 54.- 



- Average quantities of certain constituents in 17 waters analyzed from Tertiary 
and older formations. ah 



Parts per 
million. 



Bicarbonate radicle (HC0 3 ) . . . 

Sulphate radicle (SO4) 

Chloride radicle (CI) 

Total hardness as CaC0 3 c 

Total dissolved solids at 180° C . 
Range of total dissolved solids . 



224 
128 
450 
395 
1,183 
d 283-3, 409 



a Based on analyses published in this report. 
* Omitting analyses of oil wells, map Nos. F 7, K 16, and K 37. 
c Computed. 

d Total solids in water from Balboa oil well, map No. K 37 (Table 57, pp. 260-261)= 8,764 parts per 
million. 

WATER FROM VALLEY FILL. 



The valley fill in the area covered by this report is found principally 
in the valleys of the major streams (see p. Ill) and consists mainly of 
unconsolidated sand and silt. Layers of coarse materials, such as 
gravel and boulders, are encountered in some places, particularly at 
or near the bottom of the valley fill, but constitute a very small part 






256 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

of the deposit. The valley fill occupies ancient steep-walled valleys, 
and is therefore sharply bounded on the sides and bottom by the 
formations in which the valleys were cut. In the highland area the 
bodies of valley fill are surrounded by crystalline rocks and residuum; 
in the coastal belt they are for the most part surrounded by Tertiary 
deposits. The major stream valleys cross both the highland area 
and the coastal belt, and the valley fill occurs, not in continuous 
deposits but in isolated bodies separated by bedrock exposures, as 
shown on the geologic map, Plate III, so that along some drainage 
courses water passes successively over several distinct deposits of fill. 
The drainage carried by Hatfield Creek, for example, is collected in 
a catchment area underlain by crystalline rocks and is discharged into 
Santa Maria Creek, whose valley contains a large deposit of valley 
fill. This deposit extends down Santa Maria Creek only as far as 
the west side of the Valle de Palmo. The creek then passes over a 
crystalline rock bed, carries water that has traversed valley fill in 
the Ramona basin, and empties into San Dieguito River in San 
Pasqual Valley. San Pasqual Valley contains a deep deposit of 
valley fill which extends west to the foot of Bernardo Mountain. 
From Bernardo Mountain to the head of San Dieguito Valley, which 
begins at the western edge of the highland area, San Dieguito River 
flows over a crystalline rock floor, and finally, through San Dieguito 
Valley it flows over valley fill. Sources of recharge in valley fill near 
the coast are: 

(1) Direct rainfall on the valley fill, (2) surface drainage, (3) 
springs and underground drainage from crystalline rocks and gra- 
nitic residuum, and (4) springs and underground drainage from the 
Tertiary sedimentary formations. 

Passing eastward from the coast, drainage from the Tertiary sedi- 
ments first ceases to be a source of recharge; and finally, as the highest 
valley-fill deposits are reached, drainage from other valley fill. Thus 
in the highland basins the sources of recharge in valley fill are: (1) 
direct rainfall, (2) surface drainage, and (3) springs and underground 
drainage from crystalline rocks and granitic residuum. 

The chemical composition of the water in any deposit of valley fill 
is determined by the mingling of waters from all the different sources 
of recharge, and by the solution of mineral substances contained in 
the valley fill itself. Twenty-five samples of water obtained from 
wells that draw their supplies from valley fill were analyzed ; of these 
19 came from fill in the coastal belt and 6 from fill in highland basins. 

The following table gives the averages of some of the constituents: 



Tai 



QUALITY OF WATEK. 



257 



able 55. — Average quantities of certain constituents in waters analyzed from valley fill 
in coastal belt and in highland basins. a 



[Ps 


irts per mil 


ion unless otherwise stated.] 








Coastal belt. 


Highland 
basins. 


Number of samples averaged 


19 
363 
215 
689 
513 
1,801 
320-5,060 


6 


Bicarbonate radicle (HC0 3 ) 


219 


Sulphate radicle (S0 4 ) 


69 


Chloride radicle (CI) 


179 


Total hardness as CaC03 b 


269 


Total dissolved solids at 180° C 


614 




352-871 







Based on analyses published in this report. 



b Computed. 



Thus, so far as shown by the analyses, the water from the fill of the 
t principal valleys in the coastal belt contains about three times as 
: much dissolved solids as the water from the fill of the major valleys 
in the highland area. According to the results of the analyses the 
: waters from the fill of the highland area range in total dissolved 
: solids from 352 to 871 parts per million and average about 614 
! parts per million, whereas the waters from the fill in the coastal belt 
have a much wider range — from 320 to 5,060 parts per million — and 
; average 1,801. 

: • Though there is wide variation in the quality of water from valley 
fill, it has not been possible to discover any consistent relation between 
: this variation and the depth or location of the wells, except as indi- 
cated above. The analyses indicate that in the valleys of the coastal 
! belt waters from wells ending in valley fill are likely to be rather 
highly mineralized, sodium-chloride waters, fair or poor for irriga- 
tion, and very bad for boilers. The waters of the coastal belt vary 
widely in their quality for domestic use; of the 19 samples analyzed 
2 are classed as good, 5 as fair, 5 as poor, 4 as bad, and 3 as unfit for 
: domestic use. The analyses in this report indicate that waters from 
wells sunk in valley fill in the highland valleys may be expected to 
; yield sodium-chloride waters of moderate mineral content, fair for 
i domestic use, fair for irrigation, and ranging from fair to very bad 
for boiler use. 
I With regard to the quality of these waters for irrigation, however, 
it should be remembered that, as stated on pages 234-235, the classifi- 
cation is based on the quantities of dissolved salts harmful to plants, 
; but that the texture of the soil and conditions affecting drainage of 
the soil may entirely prevent accumulation of alkali, so that under 
favorable conditions waters classified as poor for irrigation may be 
used successfully. A large number of wells are now being pumped 
for irrigation and the results have been sufficiently encouraging to 
stimulate active interest in the use of ground water supplies for this 
purpose. That some care is necessary to insure success in the use 
115536°— 19— wsp 446 17 



d. 



258 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

of highly mineralized waters is, however, illustrated by a more or 
less accidental result obtained in Sweetwater Valley, where a well 
(O 22) drilled in Sweetwater Valley to the depth of 900 feet encoun- 
tered an artesian flow of very salty water (see Table 59, p. 263) in 
Tertiary beds underlying the valley fill. Being unfit for use it was 
permitted to run unchecked for a number of years, and it is said that 
land for a considerable distance down the valley became seriously 
damaged by salt water. The water in this well is said to have gradu- 
ally decreased in salinity, however, and the flow was finally stopped. 
According to information obtained from gardeners in the vicinity the 
land that had been damaged by this well has gradually improved 
Owing to the high porosity of valley fill in this area and the favorabl 
conditions for soil drainage, and especially owing to the natur 
flushing of the lowlands during flood seasons, it is believed that in 
general the use of valley-fill waters for irrigation will cause no serious 
alkali trouble. 

QUALITY IN RELATION TO USE FOR IRRIGATION. 

Irrigation at the present time is almost entirely confined to area' 
underlain by valley fill and residuum, which together comprise an 
exceedingly small part of the region and are naturally so well adapted 
to irrigation that injurious effects of poor waters are likely to be slow 
to manifest themselves. Valley fill and residuum lands are much 
better adapted to the use of highly mineralized waters than are the 
terrace or mesa lands underlain by Tertiary deposits, because both 
the valley fill and the residuum are much more porous, and in most 
places they are naturally well drained, so that there is probably no 
serious danger of the soils becoming so highly impregnated with 
alkali as to inhibit the growth of plants. 

The lands on Linda Vista and Otay mesas, however, owing to the 
density of the soils and underlying rocks, may present difficult prob- 
lems if ways are found to bring them under irrigation. These lands, 
reaching in unbroken stretches over hundreds of square miles, con- 
stitute by far the largest part of the coastal belt. (See PI. II.) They 
are covered by tillable soils, probably as good and in some places 
even better than valley lands now cultivated, but they remain almost 
entirely unoccupied because of the absence of water. Water is, of 
course, the first need; its quality, provided it is not unfit for irriga- 
tion, being a minor consideration and the chemical problems that 
may be encountered in irrigation will no doubt appear trifling after 
overcoming the difficulties of obtaining the water. 



QUALITY OF WATER. 
QUALITY OF SURFACE WATERS. 



259 



This investigation did not afford an opportunity to make a detailed 
study of the quality of surface waters. However, seven samples were 
obtained from selected localities and the results of their analysis are 
given in the following table: 

Table 56. — Partial analyses a of surface waters. 
[Parts per million. Alfred A. Chambers and C H. Kidwell, analysts.] 



Constituents. 



Suspended matter 

Silica (SiOj) 

Iron(Fe) 

Calcium (Ca) 

Magnesium (Mg) 

Sodium and potassium(Na+K)& 

Carbonate radicle (C0 3 ) 

Bicarbonate radicle (HC0 3 ) 

Sulphate radicle (S0 4 ) 

Chloride radicle (CI) 

Nitrate radicle (N0 3 ) 

Total dissolved solids at 180° C. . 
Date of collection (1918) 



278 
13 

.18 
23 
7.0 
33 

.0 
119 
23 
26 

Tr. 
188 
Mar. 16 



42 
34 
1.4 
18 
7.1 
18 

.0 

79 

21 

18 

.40 

176 

Mar. 8 



2.7 
34 

.06 
33 
17 
26 

.0 

129 

50 

36 

Tr. 

264 

Mar. 7 



120 



42 



.0 

145 

32 

68 

.22 

307 

Mar. 16 



56 
37 

.09 
40 
12 
64 
7.2 
183 
32 
65 

Tr. 
346 
Mar. 10 



52 
32 

.06 
37 
18 
49 

.0 

188 

40 

55 

.16 

323 

Mar. 10 



12 
39 

.04 
50 
19 
77 
5.8 
• 251 
30 
87 

Tr. 
429 
Mar. 10 



a For methods used in anlyses and accuracy of results, see pp. 222-223. 



t> Computed. 



1. San Luis Rey River (Escondido canal intake, sec. 32, T. 10 S., R. 1 E.), about 3 miles east of Rincon 
Indian Agency, Calif. 

2. Santa Ysabel Creek about 7 miles northeast of Ramona, Calif. (SW. I sec. 17, T. 12 S., R. 2 E.). 35 
second-feet in creek Mar. 6, 1918. 

3. San Diego River about 15 miles northeast of Lakeside, Calif. (NE. J sec. 2, T. 14 S., R. 2 E.). 7.8 
second-feet in river Mar. 7, 1918. 

4. San Diego River at Mission dam, about 7 miles west of Lakeside, Calif, (at bench mark near west 
boundary of El Cajon land grant). 189 second-feet in river Mar. 16, 1918. 

5. Sweetwater River at Dehesa, Calif, (sec. 14, T. 16 S., R. 1 E.). 14 second-feet in river Mar. 10, 1918. 

6. Jamul Creek about 6 miles west of Dulzura, Calif, (southwest portion of Jamul land grant). Sample 
collected at point below entrance of aqueduct from Cottonwood Creek— sample is a mixture of waters 
from Jamul and Cottonwood creeks. The raw water forms part of the public water supply for San Diego, 
Calif. 

7. Cottonwood Creek about 5 miles southeast of Dulzura, Calif. (N. ?, sec. 26, T. 18 S., R. 2 E.). Water 
from Cottonwood Creek is diverted at Barrett dam into Jamul Creek. 5 second-feet in river Mar. 10, 1918. 






260 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



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263 



[Parts per million; samples collected June, 1915; assayed by S. C. Dinsmore. For records of wells and 
springs, see corresponding numbers in Table 46, opposite p. 222.] 



QUALITY OF WATER. 

Table 59. — Incomplete laboratory assays of water from wells and springs. 



No. on PI. II. 


Iron(Fe). 


Carbonate 
radicle 
(C0 3 ). 


Bicarbon 

ate radicle 

HCO3). 


Sulphate 
radicle 
(S0 4 ). 


Chloride 

radicle 

(CI). 


C2 


Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 

0.34 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 

.09 
Tr. 
Tr. 


































































168 
217 
639 
346 
344 
346 
234 
224 
161 
217 
193 

56 
227 
471 
256 
395 
364 
112 
461 
476 
283 
146 
315 
168 
390 
159 
168 
163 
154 
361 
271 
163 
398 
190 
171 
188 
178 
266 
178 
293 
307 
263 
476 
288 
686 

30 
144 
183 
251 
249 
266 
249 
300 
354 
298 
429 
271 

53 
290 
288 
337 
207 


84 
37 
431 
35 
50 
104 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
Tr. 
74 
103 
176 
406 
481 
56 
456 
181 
56 
Tr. 

108 
Tr. 
215 
49 
Tr. 

38 
Tr. 
168 
64 
£6 
42 
Tr. 
61 
66 
46 
50 
Tr. 
Tr. 
37 
37 
140 
36 
104 
138 
49 
61 
30 
Tr. 
Tr. 
Tr. 
256 
222 
97 
229 
108 
Tr. 
82 
81 
83 
36 


39 
85 
703 
188 
515 
167 
42 


J 1 2 


F3 


■p 4 


Q. 17 


Q Jg 


H 2 


H3 


46 


H 4 


50 


H5 


39 


H6 


50 


K24 1 = 


60 


K 33 


213 


K 35 


348 


K 36 


238 


K38 


1,050 
813 


K42 


K43 ■--.- 


135 


K 46 


788 


K 48 


177 




181 


K50 


60 




366 


K52 


99 




419 


L6 


60 




64 


L 10 


85 




209 


L12 


426 




149 


L 15 


121 




284 


L20 .- 


106 




501 


L24 .. 


486 




586 


L31 


256 




60 


L 39 


163 


L40 


202 




96 


L42 


518 




217 


21 . . . . . 


1,160 




1,300 
440 


34 




422 


37 


199 




170 


43 


156 




170 


47 , 


1,260 


51 


511 


52 


195 


53 


387 


54 


217 


55 


124 


56 


177 




185 


PI 


199 




249 







264 

TESTS OF PUMPING PLANTS. 

By C. H. Lee. 

PURPOSE OF TESTS. 

Examinations and tests of pumping plants of various types were 
made by the writer in June, 1915, to determine under actual condi- 
tions on the farm the efficiency of pumps and the over-all efficiency 
of pumping plants and the cost of pumping water for irrigation. 

The efficiency of a pump is the percentage of the useful work done 
to the total power delivered to the pump. The difference between 
the efficiency and 100 per cent represents the power which is wasted 
by friction in the pump but which must be paid for by the owner 
of the plant, who should therefore understand clearly the conditions 
that tend to increase or decrease the proportion of power wasted. 
The efficiency of a pump as measured at the well is very commonly 
much below that claimed by the manufacturer's catalogue and the 
sales agent, chiefly because the pump is operated under conditions 
entirely different from those for which its efficiency was determined 
for the manufacturer's catalogue. Thus, although the manufacturer's 
rated efficiency can probably be realized under the prescribed condi- 
tions of head, speed, and discharge, the actuai efficiency realized 
under the conditions prevailing where the pump is used may be much 
lower. 

Moreover, the efficiency of the pump may be much greater than 
the over-all efficiency of the plant, owing to loss of energy in trans- 
mission from the motor or engine to the pump. The efficiency of 
pumps and plants can be shown only by tests made on plants actually 
installed. Such tests not only assist the owners of pumping plants 
to determine whether their plants are operating efficiently and 
economically, but also furnish a basis for rules that should be followed 
in selecting and installing new plants. 

The result of such tests that is perhaps the most valuable to the 
irrigator is the determination of the cost of pumping water for irriga- 
tion. In this day, when so much is said and written to show what 
enormous profits may be made by irrigation with pumped water, 
there is great need of careful investigation to determine as accurately 
as possible the most economical method of pumping for irrigation 
under every set of local conditions. To the farmer who contemplates 
putting in a pumping plant for irrigation, the investigation furnishes 
a means of determining whether it is likely to be a paying investment; 
to the farmer who is already operating a plant, a comparative study 
of the cost of pumping in other plants may indicate whether his water 
is costing too much and may suggest methods by which the cost 
can be decreased and the profits increased. 



TESTS OF PUMPING PLANTS. 265 

The pumping plants selected for tests were only those which could 
be considered representative of type of well, formations penetrated, 
and choice and manner of installation of machinery, plants of very 
poor design or in bad repair being, so far as possible, avoided. Tests 
were made of seven motor-driven plants and of one gasoline-engine 
plant, but as the test of the gasoline-engine plant did not prove 
satisfactory the results were rejected. The owners and operators of 
the plants cooperated heartily, and the success of the tests is due in 
no small degree to the valuable assistance and information they so 
cheerfully furnished. 

METHODS USED IN TESTS. 
EQUIPMENT. 

The following equipment was carried and used as required to 
supplement permanent equipment found at the plants: 

1 0-300-pound pressure gage. 
1 vacuum gage. 
1 small Price current meter. 
1 Fahrenheit thermometer. 
1 100-foot steel tape. 

1 stop watch. 

2 speed indicators. 
1 small spirit level. 
1 hand level. 

1 4-foot folding rule. 
1 hook gage, reading to 0.001 foot. 
1 Cippoletti weir board, with 24-inch crest. 

Miscellaneous small tools, such as drills, pliers, screw driver, wrenches, J-inch pipe 
nipples, and fittings for use with gages. 

The pressure gage was calibrated against a standard and was found 
to be correct when registering more than 9 feet of water pressure. 
The vacuum gage was new and checked closely with one known to 
be correct. The current meter, which had been recently rated, was 
in excellent condition. The Cippoletti weir board was made of 1-inch 
redwood and was 6 feet long and 2 feet wide; the notch was 7 inches 
deep and 24 inches long on the bottom; galvanized sheet iron was 
fastened to the upstream face of the notch with screws and nails, 
and the wooden edge was beveled on the downstream side so as to 
insure a free fall of the water. A burlap apron was tacked to the 
board on each side to prevent the water from leaking around the weir. 

MEASUREMENTS AND COMPUTATIONS. 

Discharge. — Wherever possible the discharge, or the quantity of 
water being lifted by the pump, was measured by the portable 
Cippoletti weir, a temporary pond with earth banks being prepared 
and the weir board placed at one end and thoroughly puddled into 



266 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

the bank. A hook gage fastened to a stake driven upstream from 
the weir was used for reading the head of water over the crest of the 
weir. The discharge was then determined from standard tables of 
discharge for Cippoletti weirs. In two tests the discharge was 
measured with the current meter; in two others it was determined 
by measuring the change in depth of water in a circular reservoir 
during the period of the test. 

Head. — The head against which a pump must operate is often erro- 
neously considered as the vertical distance between the water surface 
in the well during pumping and the point of free discharge or, when 
the discharge is submerged, the level of the water in the reservoir 
or standpipe. The actual head, however, is always greater than this 
static head, for the pump must also operate against a head made up 
of the losses due to friction in the discharge and suction pipes. 
Pump efficiency computed from static head alone is therefore too low. 
In these te§ts the total head was obtained, where possible, by installing 
pressure and vaccum gages and observing the pressure heads and 
suction heads, and adding to this observed head the measured vertical 
distance between the center of the pressure gage and the point of 
insertion of the vacuum gage. This method gives the true total 
head against which the pump operates and includes the difference of 
elevation through which the water is lifted as well as the head due to 
losses by friction in the suction and discharge pipes. It does not 
include the head represented by the velocity of discharge, and 
although engineers differ in opinion as to whether it should be credited 
to the pump, it was not taken into account in these test's. 

Where it was impossible to install the pressure and vacuum gages 
the total head was determined by adding to the difference in elevation 
between the surface of the water in the well and the point of discharge, 
the head lost by friction in pipe and bends, computed by the usual 
hydraulic formulas. 

Speed. — The speed of motors and pumps was measured by means of 
a speed counter and stop watch. In plants provided with belt trans- 
mission from motor to pump, loss of power in transmission was deter- 
mined by measuring the speed of both drive and pump pulleys as 
nearly simultaneously as possible. Several readings were made dur- 
ing each test, and the mean result was taken as the determined speed. 
Water horsepower. — " Water horsepower," as the term is used in 
these tests, is the product of the discharge in gallons per minute by 
the weight of a gallon of water in pounds by the total head in feet, 
divided by 33,000, the number of foot-pounds per minute equivalent 
to one horsepower. Total head is the head made up of the static 
head plus head due to losses by friction in suction and discharge 
pipes. 



1 



TESTS OF PUMPING PLANTS. 267 

Power input. — The power input of the pumping plants, all of which 
were motor-driven electrical plants, was measured in kilowatts at the 
beginning and the end of the test by reading the watt meters installed 
by the power company. The difference between these readings gave 
the number of kilowatt-hours of power used during the period of the 
test, from which, the meter constant and the duration of the test in 
hours being known, the power input in kilowatts was computed and 
reduced to horsepower. In all the tests the speed of the meter disk 
was read and the power input in kilowatts was computed as a check 
on that obtained from the meter readings. The number of kilowatts 
as derived from the meter readings was used in all the tests except 
one, as it gave a better average determination for the power input, 
from which the plant efficiency was determined. 

Horsepower input at pump. — The horsepower input at the pump, 
used in determining pump efficiency, was computed by subtracting 
from the electrical horsepower input at the motor the power lost in 
the motor and in the transmission from motor to pump. The power 
lost in the motor was computed from the efficiency of the motor as 
shown by the efficiency curves furnished by the manufacturers. 
Part of the loss in belt transmission was determined by comparing 
the measured speed of the pump pulley with its theoretical speed as 
computed from the measured speed of the drive pulley and the ratio 
of pulley diameters. Other belt losses are small and no attempt was 
made to determine them. The loss in gear transmission was com- 
puted by Goodman's empirical formula for efficiency of toothed gears. 

Pump efficiency. — The pump efficiency is the ratio of the water 
horsepower to the horsepower input at the pump. In many efficiency 
tests of installed irrigation pumps the loss in transmission between 
motor or engine and pump has been charged to the pump. This 
practice is manifestly unfair to the pump, and care was taken in 
these tests and computations to obtain as closely as possible the 
actual power input at the pump. 

Plant efficiency. — The plant efficiency is the ratio of the water 
horsepower to the electrical horsepower input at the motor, as deter- 
mined from the watt-meter readings of power consumed during the 
test. It differs from pump efficiency in that it includes, besides such 
losses as those in pump and piping, the losses in the motor and in 
transmission from motor to pump. 

RESULTS OF TESTS. 
PUMPING PLANT AT WELL O 132. 

The plant at well O 132 is in Tia Juana Valley, 2 miles southeast 
of Nestor, in sec. 34, T. 18 S., R. 2 W., and is owned by C. M. Richard- 
son. It was tested June 19, 1915, at which time it had been in 
operation two years. 



268 GKOUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



The equipment consisted of a 20-horsepower, 3-phase, 220-volt 
motor, rated at 1 ,200 revolutions per minute, direct-connected to a 
6-inch centrifugal pump, rated at 900 gallons per minute at 1,120 
revolutions per minute when operating against a 40-foot head. The 
discharge pipe was 8 inches in diameter and 19.5 feet long. 

Pump and motor were placed in the bottom of a circular concrete 
pit, 12 feet in diameter and 12 feet deep, a shed housing all. On a 
level with the bottom of the pit was a horizontal suction pipe, 8 inches 
in diameter and 76 feet long, from which vertical connections 9 feet 
long were dropped into each of two drilled wells, 72 feet apart, sunk 
to a depth of 68 feet below the surface of the ground, lined to the 
level of the horizontal suction pipe with 12-inch casing perforated 
along the lower 12 feet. 

The pressure gage could not be used with the low head existing, 
so that the total head was obtained by adding the suction head as 
observed with the vacuum gage, the measured vertical distance be- 
tween vacuum gage and point of discharge, and the estimated head 
lost by friction in the discharge pipe. The discharge was measured 
with the current meter in a wooden flume that carried the water 
from the pump. The power input was obtained from readings of 
the watt meter at the beginning and the end of the test. 

Summary of results of test at well 132. 

Duration hours. . 1 

Speed of motor revolutions per minute . . 1, 120 

Speed of pump do 1,120 

Depth of normal water level below the ground surface (approxi- 
mate) feet.. 9 

Drawdown (estimated) do— ... 27 

Total head (estimated) do 44. 5 

Discharge gallons per minute . . 1, 120 

Water horsepower 12. 6 

Power input kilowatt hours. . 14 

Power input horsepower. . 18. 75 

Motor efficiency ' per cent. . 88 

Horsepower input at pump 16. 5 

Pump efficiency per cent. . 76. 5 

Plant efficiency do 68. 5 

PUMPING PLANT AT WELL K 41. 

The plant at well K 41 is in Mission Valley, about 5 miles north- 
east of San Diego, and is owned by C. A. Van Houten. It had been 
in operation six months when the test was made, June 21, 1915. 

The equipment included a 20-horsepower 3-phase 220-volt motor, 
rated at 1,200 revolutions per minute, direct-connected to an 8-inch 
centrifugal pump having a discharge pipe 10 inches in diameter and 
16.7 feet long. The suction line ranged from 8 inches to 4 inches 



TESTS OF PUMPING PLANTS. 



269 



in diameter, the horizontal part being composed of 120 feet of 8-irich, 
60 feet of 6-inch, and 60 feet of 4-inch pipe. 

Pump and motor were in the bottom of a circular concrete pit, 
8 feet in diameter and 9.5 feet deep. From the horizontal part of 
the suction line, which extended out from and on a level with the 
bottom of the pit, a 4-inch pipe, 35 feet long, extended into each of 
five drilled wells, spaced 60 feet apart, sunk to an average depth of 
80 feet, and lined with 10-inch standard screw casing which was 
perforated with drilled holes along the lower 10 feet in each well; 
the well casings extended only to the suction line. One of the wells 
was directly below the bottom of the pit and the others were out- 
side. The well farthest from the pump was in an open pit extending 
from the horizontal suction pipe to the surface of the ground; the 
other wells were buried. 

Two test runs were made. The pressure gage could not be used 
at the low head existing, and the total head was obtained by adding 
the suction head as observed with the vacuum gage, the measured 
vertical distance between the vacuum gage and point of discharge, 
and the estimated head lost by friction in the discharge pipe. The 
pump was leaking air badly during both tests, and just at the con- 
clusion of the second run entirely stopped delivering water. The 
discharge in the first run was measured by current meter in the ditch 
that carried water from the plant; for the second run it was meas- 
ured by both weir and current meter, the two determinations check- 
ing closely. The power input for both runs was obtained from 
readings of the speed of disk in the watt meter. 

Summary of results of test of well K 41. 



First 
run. 




Second 
run. 



Duration hours . . 

Speed of motor revolutions per minute. . 

Speed of pump do 

Depth of normal water level below ground surface (approximate) feet . . 

Drawdown a (approximate) do 

Total head (estimated) : do 

Discharge gallons per minute. . 

Water horsepower 

Power input kilowatt hours. . 

Power input horsepower. . 

Motor efficiency per cent. . 

Power input at pump horsepower. . 

Pump efficiency per cent. . 

Plant efficiency do 



1.35 
1,170 
1,170 



22 

36.7 
614. 
5.7 
16.9 
17.21 
87 

15.0 
38 
33 



a Final drawdown at end of second run after five hours continuous pumping; the rest of the data for 
the two runs being taken during this time. 



PUMPING PLANT AT WELL O 115. 



The plant at well O 115 is 1J miles south of Nestor, on the north 
edge of Tia Juana Valley, in sec. 34, T. 18 S., R. 2 W., and is owned 
by W. E. Williams. The test was made June 24, 1915, at which 
time the plant had been in operation two years. 



270 GKOUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

The equipment consisted of a 5-horsepower 3-phase 60-cycle 220- 
volt motor, rated at 1,800 revolutions per minute, belted with 3|-inch 
4-ply stitched canvas belt to a centrifugal pump with 3J-inch suction. 
The discharge pipe was 4 inches in diameter and 21.5 feet long. The 
suction pipe was 4 inches in diameter and 27 feet long. 

The motor was on the ground-surface level, housed in a shed, and 
the pump was set in the bottom of an open-dug pit, 5 feet square 
and 7.5 feet deep, curbed with redwood boards. The belt connecting 
pump and motor ran through an inclined trench, the motor and 
pump being spaced 17.8 feet, center to center. From the bottom of 
the pit a single drilled well, lined with unperf orated 10-inch casing 
and drawing water only from the bottom, was sunk to a depth of 
56 feet. 

The plant was in poor running order. The curbing was in bad 
condition, a result of the wet weather of 1914-15. The bottom of the 
pit was a bog of quicksand, silt, and water, and streams of water 
were entering the well casing. The slush and water with which the 
pump pulley and belt were in continuous contact caused much slip- 
page in the belt and very uneven discharge. The discharge was 
measured with the 2-foot Cippoletti weir. Owing to the impossi- 
bility of installing- the vacuum and pressure gages, the total head 
was estimated by adding the measured distance from the average 
drawdown of the water level to the point of discharge and the esti- 
mated loss of head due to friction in pipe and bends. The power 
input was obtained -from readings of the watt meter at the beginning 
and the end of the test. 

Summary of results of test at well 115. 

Duration hours. . 1. 1 

Speed of motor revolutions per minute . . 1, 783 

Speed of pump do 795 

Depth of normal water level below ground surface feet. . 8. 1 

Drawdown do 15.25 

Total head (estimated) do 28. 7 

Discharge. . . .• gallons per minute. . 231. 

Water horsepower 1. 7 

Power input kilowatt hours. . 5. 3 

Power input horsepower. . 6. 45 

Motor efficiency percent.. 86 

Belt efficiency (assumed) do 90 

Power input at pump horsepower. . 4. 99 

Pump efficiency per cent. . 34 

Plant efficiency do 26 

PUMPING PLANT AT WELL O 47. 

The plant at well O 47 is 1| miles west of Nestor, in the SW. I 
sec. 29, T. 18 S., E. 2 W., and is owned by Tucker and Evans. The 
test was made June 18, 1915, at which time the plant had been oper- 
ated two years. 



TESTS OF PUMPING PLANTS. 271 

The equipment consisted of a 10-horsepower 3-phase 60-cycle 
220- volt motor, rated at 1,800 revolutions per minute, direct-con- 
nected to a 4-inch centrifugal pump with rated discharge of 400 gal- 
lons per minute at 1,740 revolutions per minute. The discharge 
pipe was 6 inches in diameter and 25 feet long. The suction pipe was 
6 inches in diameter and 30 feet long. 

The plant is of modern design, the pump and motor being placed 
in a concrete pit 4.7 feet by 8.5 feet and 19 feet deep, a shed housing 
the whole. From the bottom of the pit a drilled well, with 12-inch 
casing, extended to a depth of 68 feet below the surface of the ground. 
The casing was said to be without perforations, the water being 
drawn into the well at the bottom. 

The total head was obtained by readings of the vacuum and pres- 
sure gages. The discharge was measured by the portable 2-foot 
Cippoletti weir. The power input was obtained from readings of 
the watt meter at the beginning and the end of the test. 

Summary of results of test at well 47. 

Duration hours. . 1. 63 

Speed of motor revolutions per minute . . 1, 732 

Speed of pump do 1, 732 

Depth of normal water level below ground surface feet . . 21 

Drawdown do 21 

Total head do ... . 53. 1 

Discharge gallons per minute . . 373. 

Water horsepower 5. 01 

Power input kilowatt hours . . 13. 

Power input horsepower . . 10. 67 

Motor efficiency per cent . . 87 

Power input at pump J horsepower. . 9. 27 

Pump efficiency per cent . . 54. 

Plant efficiency do 47. 3 

PUMPING PLANT AT WELL O 102. 

The plant at well O 102 is 1 mile east of Nestor, in the SE. \ sec. 
27, T. 18 S., R. 2 W., and is owned by R. J. Jaeger. The test was 
made June 18, 1915, when the plant had been in operation two years. 

The equipment included a 10-horsepower 3-phase 220- volt motor, 
rated at 800 revolutions per minute, geared to a deep-well recipro- 
cating pump with 8-inch cylinders and 15-inch stroke, whose rated 
capacity was 243 gallons per minute at 40 strokes per minute. The 
discharge line was made up of 90 feet of 10-inch pipe and 112 feet of 
6-inch pipe. The suction pipe was 8 inches in diameter and 18 feet 
long. 

Pump head and motor were placed at the ground-surface level and 
were supported on timbers spanning an open dug pit, 4 feet square 
and 110 feet deep, curbed with concrete. From the bottom of the 



272 

pit a drilled well, lined with 12-inch casing, extended to a depth of 
20 feet below the bottom of the pit, the casing protruding 10 feet 
above the bottom of the pit. 

The total head was obtained by adding the measured distance from 
the water level in the pit during pumping to the point of discharge 
and the estimated head due to losses from friction in the discharge 
and suction lines. The discharge was obtained by measuring the 
depth of water at the beginning and end of the test in a concrete cir- 
cular reservoir. The power input was obtained from readings of 
the watt meter at beginning and end of test. 

Summary of the results of test at well 102. 

Duration hours . . 2. 1 

Speed, of motor revolutions per minute . . 862. 2 

Speed of pump strokes per minute . . 25. 4 

Depth of normal water level below ground surface feet . . 84. 

Drawdown .'. Inappreciable. 

Total head (estimated) feet . . 97. 4 

Discharge gallons per minute . . 116 

Water horsepower 2.9 

Power input kilowatt hours . . 13. 

Power input horsepower . . 8. 32 

Motor efficiency per cent . . 86 

Power input at pump horsepower. . 7. 15 

Pump efficiency a per cent . . 40. 6 

Plant efficiency per cent. . 35. 

PUMPING PLANT AT WELL L 24. 

The plant at well L 24 is about half a mile north of El Cajon and is 
owned by Joseph Miller. The test was made June 22, 1915, when 
the plant was only 3 months old. 

The equipment consisted of a 5-horsepower 3-phase 60-cycle 
220-volt motor, rated at 1,700 revolutions per minute, direct-con- 
nected to a centrifugal pump rated at 225 gallons per minute when 
pumping against a 40-foot head. The pump suction was 2\ inches 
in diameter, and the suction pipe was 4 inches in diameter and 26 
feet long. The discharge pipe was 3 inches in diameter and 32.85 
feet long. 

The plant was thoroughly modern and well equipped. Pump and 
motor were set in the bottom of a water-tight concrete pit, 5 feet in 
diameter and 25 feet deep, protected by shed housing, and distant 
about 8 feet from the open dug well, 7.5 feet in diameter and 50 feet 
deep, curbed with concrete. The normal water level was thus 
always above the level of the pump and hence no priming was re- 
quired. About 7 feet up from the bottom of the well five 2-inch 

a Pump efficiency includes loss in gears of pump head, which is standard equipment of the manufac- 
turing concern, and therefore is a loss whose effect should he included in the pump efficiency. 



TESTS OF PUMPING PLANTS. 273 

auger-hole borings extended radially from the well, for distances 
ranging from 60 to 131 feet, into the water-bearing residuum. 

The head was obtained by readings of the vacuum and pressure 
gages. The discharge was r ctsured by means of the 2-foot Cippo- 
letti weir. The power ir>\^c was obtained by readings of the watt- 
meter at beginning and end of test. 

Summary of the results of test at well L 24 . 

Duration hours . . 20. 8 

Speed of motor (average) revolutions per minute . . 1, 714 

Speed of pump do 1, 714 

Depth of normal water level below ground surface feet . - 9.5 

Drawdown do 20.8 

Total head , do 46. 35 

Discharge gallons per minute . . 156 

Water horsepower 1. 83 

Power input kilowatt hours . . 73. 6 

Power input horsepower.. 4.74 

Motor efficiency per cent . . 85 

Power input at pump horsepower. . 4. 04 

Pump efficiency per cent. . 45. 3 

Plant efficiency do 39. 3 

PUMPING PLANT AT WELL L 98. 

The plant at well L 98 is 2 miles east of El Cajon and is owned by 
Charles Bentley. The test was made June 23 and 24, 1915, at which 
time the plant had been in operation 1 1 months. 

The equipment consisted of a 5-horsepower 3-phase 60-cycle 220- 
s volt motor, rated at 1,800 revolutions per minute, connected by a 
) very short 3-inch leather belt to the pump head of a duplex displace- 
ment pump, with cylinders 5 inches in diameter and stroke 27 
inches. There were 61.2 feet of 6-inch suction and discharge pipe 
and 47.7 feet of 4-inch discharge pipe. 

i The well was a dug pit, 7 feet 2 inches in diameter for the first 6 
<feet (where it was curbed), 4 feet 6 inches in diameter to a depth of 20 
^feet, and 6 feet in diameter for the remainder to a total depth of 68 
feet. There were no laterals. Pump and motor were supported on a 
platform over the pit and the whole was housed by a shed. The 
pulley wheel to which the motor was belted operates a train of gears 
which finally operates the connecting rods of the pump cylinders. 
The belt showed much tendency to -slipping. Considerable vibration 
of the pump rods was observed. 

Tests were made for three runs. The total head in each run was 
determined by adding the measured distance from the average water 
level in the well to the point of discharge and the estimated head lost 
in friction. The discharge was determined by measuring the depth, 

I it the beginning and end of the test, in the circular wooden tank that 
115536°— 19— wsp 446 18 



274 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

received the water. The power input was obtained from readings of 
the wattmeter at beginning and end of test. 

Summary of results of test at well L 98. 



First 
run. 



Second 
run. 



Third 
run. 



Duration hours . . 

Speed or motor revolutions per minute . . 

Speed of drive pulley on pump do 

Depth of normal water level below ground surface (approximate) . . .feet. . 

Drawdown a do 

Totalhead do.... 

Discharge gallons per minute. . 

Water horsepower 

Power input kilowatt hours. . 

Power input horsepower. . 

Efficiency of motor percent.. 

Efficiency of belt do — 

Power input at pump horsepower. . 

Pump efficiency per cent . . 

Plant efficiency do 



1.2 



258 
11 



0.45 
1,766 
258 



0.98 

1,750 

262 



62.9 

82.0 
1.3 
3.05 
3.41 

84 

90.0 
2.57 

51 

38 



24.73 

77.1 

75.2 
1.5 
1.1 
3.27 

84 

90.2 
2.48 

60 

45 



56. 5 

79.9 
1.1 
2.55 
3.37 

84 

89.9 
2.54 

45 

34 



a Drawdown reached at end of second run after 3 hours and 35 minutes continuous pumping, during 
which other data for runs 1 and 2 were obtained . 

DISCUSSION OF TESTS AND COST OF PUMPING. 
ESTIMATES OF FIXED CHARGES. 

The results of the foregoing tests are summarized in Table 61, 
in which are included also data concerning the cost of pumping at 
each plant. 

Information as to the cost of the plant and well, the cost of repairs 
and attendance, the number of hours during the year each plant was 
run, and the unit cost of fuel was obtained from the owners of the 
plants. For estimating the fixed charges of interest, depreciation, 
repairs and maintenance, taxes and insurance, it was assumed that 
the percentages in Table 60 represent nearly the actual costs under 
these heads for the average pumping plant in San Diego County. 

Table 60. — Assumed fixed charges for pumping plants, expressed as per cent of total cost 

of plant. 



Gasoline- 
engine 
plant. 



Motor- 
driven 
plant. 



Depreciation 

Interest 

Repairs and maintenance 
Taxes and insurance 



TESTS OF PUMPING PLANTS. 



275 



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276 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

The rate of depreciation of pumping plants varies through an 
enormous range, not only as a whole but in its several parts. It de- 
pends mainly on the skill and care of the attendant. The assumed 
percentages give a fair estimate of cost of depreciation where reason- 
able care in attendance is exercised. The actual cost of repairs and 
maintenance is difficult, and for some plants impossible to determine, 
owing to the fact that few owners of pumping plants keep accurate 
account of such expenses, and even if a record has been kept it does 
not cover a sufficient number of years to give a figure that will 
represent the average annual cost of repairs and maintenance. The 
percentage assumed is, therefore, based largely on data gathered in 
previous investigations of the cost of pumping in other localities. 

None of the owners of tested plants reported expense of attendance 
as part of the cost. This failure to report it does not mean that the 
plant required no attendance, but that the owner himself spends as 
much time as is necessary in caring for the plant during his odd 
moments. Strictly speaking, charge for the time spent by the 
farmer in that way should be added to the annual cost, for though 
motor-driven plants require little or no attendance while running, 
gasoline-engine plants sometimes require a great deal of attendance. 
However, if the plant is in good running order the amount of neces- 
sary attendance is small and its cost is usually negligible. 

The investigations of plant and pump efficiency and cost of pump- 
ing, summarized in Table 61, cover only in part the range of condi- 
tions of installation of pumping plants; for, so far as possible, plants 
were selected which were in good repair and of good design. They do, 
however, cover the range of capacities and equipment commonly 
found in small pumping plants used for irrigation, and the results, 
therefore, indicate those that may be obtained in plants which are 
of reasonably good design and are maintained in good running order. 
A study of the table brings out some very interesting facts. 

PUMP EFFICIENCY. 

Centrifugal pumps ranged in efficiency from 34 per cent for a 3§-inch 
pump to 76.5 per cent for a 6-inch pump, the efficiency increasing, 
other things being equal, with the size of the pump. The efficiency 
of 76.5 per cent for the 6-inch pump (well O 132) and 45 per cent for 
the 2J-inch pump (well L 24) is unusually high for pumps of these 
sizes, and shows not only thaj, the plants have been well designed and 
are in good running order, but that during the last few years the 
manufacturers have greatly improved the design of centrifugal 
pumps for small pumping plants for irrigation. The efficiency of 38 
per cent for the 8-inch centrifugal pump (well K 41) is low for a 
pump of that size, but is due to the fact that the pump was leaking 
air badly during the test. The efficiency of 34 per cent for the 3 J-inch 



TESTS OE PUMPING PLANTS. 277 

pump (well O 115) is also lower than it should be, but the reason is 
not apparent from the data obtained, except that the whole plant was 
in poor running order. 

The efficiency given by the tests of the reciprocating pumps may 
be considered fair and to fall within the limits of efficiency generally 
given by pumps of this type. 

PLANT EFFICIENCY. 

The table shows plant efficiency ranging from 26 per cent to 68.5 per 
cent, the less efficient being, as was to be expected, the smaller plants. 
The range is that generally found in practice, although 68.5 per cent 
is unusually high. The efficiency of the plants equipped with recipro- 
cating pumps is not relatively high, that of the plant with the duplex 
pump (well L 98) being much lower than it should have been, on 
account of the excessive loss in transmission due to belt slippage. 
The deep- well pump at well O 102 might have shown greater effi- 
ciency in both plant and pump if it had been operating more nearly at 
its rated capacity and speed and for conditions more nearly suited 
to a pump of this type. 

In regard to power consumed, the summary shows that under the' 
best conditions the larger motor-driven plants consume 1.1 kilowatts 
per water horsepower and the smaller plants about 1.9 kilowatts. In 
this connection attention is called to the great increase in consump- 
tion of power due to poor repair or poor design of plant, as is clearly 
shown in the tests of wells K 41 and O 115. The pump at well K 41 
was leaking air badly at the time of the test; the pump at well O 115 
was either of poor design or in poor running order, and, moreover, 
was handicapped by excessive slippage of the belt. The owners of 
such plants are paying much more for the water pumped than is 
necessary and could greatly reduce costs by making the necessary 
improvements or repairs, the expense of which would probably be 
small as compared with the loss resulting from running a plant in 
poor repair or of poor design. 

COST OF PUMPING. 

In regard to the cost of pumping — total and in detail — Table 61 
furnishes information of much interest. The cost of electricity for 
motor-driven plants is not so great a part of the expense of pumping 
as is commonly believed. For the plants tested, the relation of the 
annual cost of electrical power to the total annual cost ranged from 
40 to 63 per cent, the average being 55 per cent. This relation, of 
course, depends on the unit cost of electrical power and on the length 
of time during which the plant is operated during the year, and may 
vary with the locality. The figures, therefore, indicate only the rela- 



278 GROUND WATERS OF WESTERN" SAN DIEGO COUNTY, CALIF. 

tion that may exist for conditions similar to those in San Diego 
County. 

The annual cost per water horsepower furnishes the best means 
of comparing the economy of pumping plants as machines for pump- 
ing water. For any type of centrifugal pump, the larger the pump 
the smaller the cost per water horsepower. 

The annual cost per acre-foot of water pumped was, perhaps, the 
item of greatest interest to the owners of the plants tested, and it 
affords also a basis for rough estimate of the total annual cost of 
pumping for any known area and duty of water. The annual cost 
per acre-foot for the plants tested ranges from $3.86 for a plant 
having a lift of 44.5 feet and a discharge of 120 gallons per minute to 
$14.69 for a plant having a lift of 97 feet and a discharge of 116.5 
gallons per minute. Out of thirteen motor-driven pumping plants 
near Pomona, Cal., tested in 1905, 1 the annual cost per acre-foot of 
water pumped ranged from $1.96 for a pump having a head of 22.5 
feet and discharging 992 gallons per minute to $19.20 for a plant 
having a head of 122.4 feet and discharging 494 gallons per minute. 

For the plants using centrifugal pumps, the annual cost of pumping 
per acre-foot of lift ranges from about $0.09 to $0.40. For four of 
the seven plants tested the costs range from $0.09 to $0.14, amounts 
that are more nearly representative of the usual range in cost of 
pumping water for plants of this type. Out of seven motor-driven 
plants equipped with centrifugal pumps near Pomona, Calif., tested 
in 1905, 2 the annual cost of pumping per acre-foot of water per foot 
of lift ranged between $0.07 and $0.45, but in five of these tests the 
cost was less than $0.16. The high cost of pumping at well O 115 — 
$0.40 per acre-foot per foot — is a striking illustration of the large 
increase in cost due to poor repair or poor design of plant. The cost 
at well O 115 is about four times as large as at well L 24, in which 
the pump is smaller. The same relation is shown in less degree at 
well K 41, where the annual cost per acre-foot per foot of lift is about 
$0.14, whereas at well O 132, which is equipped with a pump of about 
the same size, the cost is $0.09. 

Another cause contributing to the high cost of pumping at well 
O 115 — a cause which must be taken into consideration — is the 
relatively small time during the year in which the plant is operated. 
The fixed charges, which make up a large part of the annual cost of 
pumping, continue at about the same rate whether the plant is being 
operated or not, and all computations in this report are based on the 
assumption that they do continue at the same rate. Therefore, 
other things being equal, the longer the period of operation during 

1 Le Conte, J. N., and Tait, C E., Mechanical tests of pumping plants in California: U. S. Dept. Agr. 
Office Exper. Sta. Bull. 181, p. 56, 1907. 

2 Idem, p. 60. 



TESTS OF PUMPING PLANTS. 279 

the year the smaller will be the unit cost of pumping the water. If, 
for example, the plant at well O 115 was operated 3,000 hours during 
the year instead of 230 hours, the total number of acre-feet pumped 
per year would be 127.7, the cost of electricity would be $563.50, 
and the total annual cost $632.50; the cost per acre-foot per foot of 
lift would then be about $0.17. This illustration shows clearly how 
great a factor the length of the pumping season is in the total cost 
of an acre-foot of water. There is ordinarily more or less oppor- 
tunity for choice between a pump of small capacity to be operated 
for a long period and a pump of larger capacity to be operated for a 
shorter period. The first cost of a plant of small capacity is less than 
that of a larger one, and hence the annual fixed charges are smaller. 
There are, of course, other factors of equal importance in the selec- 
tion of pumping machinery which are not to the advantage of the 
small plant. For example, the use of a small plant requires a longer 
period of irrigation and of attendance in operation than the use of a 
larger plant and also gives a lower efficiency. 

The cost per acre-foot of pumping with the reciprocating pumps is 
shown by the results of these tests to be high compared with that for 
the centrifugal pumps. The tests made are not strictly comparable, 
however, on account of differences in lift and capacity, but they show 
the limitation in head and capacity for which reciprocating pumps 
can be economically used. The lifts under which these pumps were 
operating are too small for their economical use. Pumps of this 
type are best suited for pumping small quantities of water from 
depths of 100 feet or more. 

SELECTION AND INSTALLATION OF PUMPING MACHINERY. 
GENERAL CONSIDERATIONS. 

The following suggestions are offered as a guide to the successful 
selection and installation of small pumping plants for irrigation. 
They are based on the best experience and practice, not only in San 
Diego County but throughout the regions in which ground water is 
pumped for irrigation. 

The problem of selecting and installing pumping machinery is much 
more difficult than many suppose. Acting on the advice of some 
sales agent who has little or no knowledge of the proper selection 
and installation of pumps, many farmers have bought pumps that 
are not well adapted for the conditions of head and discharge under 
which they must operate, or have selected and installed a gasoline 
engine or an electric motor which has either too little power and thus 
will not operate the pump at the desired capacity, or has much more 
power than is necessary and thus causes undue loss of energy in 
operation at part load. In many plants that use belt transmission 



280 GROUND WATERS OF WESTERN SAN DtEGO COUNTY, CALIF. 

between pump and motor or engine the pulleys are improperly pro- 
portioned or there is excessive belt slippage, so that the pump, or the 
engine, or the motor, or possibly all, may be running at improper 
speed. The problem not only includes a choice of the proper size 
and type of the various units of the plant, but a choice of a method 
of installation that will insure operation at the highest efficiency and 
furnish the desired quantity of water at a minimum cost. - 

Mistakes in selecting and installing pumping machinery are expen- 
sive, and anyone who contemplates installing a pumping plant that 
involves an expenditure of $600 or more for equipment would do well 
to consult some reputable engineer, experienced in the design, selec- 
tion, and installation of pumping plants for irrigation. 

PUMPS. 
CAPACITY OF PTJMP. 

The capacity of the pump required to furnish water for irrigation 
depends on the area to be irrigated, the total depth of water necessary 
for properly irrigating the crop, and the length of the period of oper- 
ation. The advantages and disadvantages of continuous operation 
with pumps of small size as compared with a shorter period of oper- 
ation with pumps of larger size have been briefly discussed on page 279. 
As a rule, a period of operation from one-half to one-third the length 
of the irrigation season is most desirable. Unless reservoirs are used, 
the pump should be large enough to give a stream sufficient to irrigate 
without great loss. To irrigate even the smallest orchard the dis- 
charge should be at least 5 to 10 miner's inches (45 to 90 gallons a 
minute), and for a crop of alfalfa on the sandy soils usual in San Diego 
County 50 to 75 miner's inches (450 to 675 gallons per minute) would 
be a minimum. On the other hand, the capacity of the pump is 
limited by the maximum yield obtainable from the well. 

To illustrate the problem of determining the necessary capacity of 
pumps: Assume a 40-acre farm planted to alfalfa, which requires 
3 acre-feet of water per acre for an irrigation season of six months, 
a quantity equal to an application of a total depth of 6 inches of 
water each month. For continuous operation, 24 hours a day, the 
necessary capacity of the pump would be 150 gallons per minute 
(16.6 miner's inches); for half-time operation, or fifteen 24-hour 
days during the month, a stream twice as large, or 300 gallons per 
minute (33.3 miner's inches), would be required; and for a one- third 
period, a stream three times as large, or 450 gallons per minute (50 
miner's inches) would be required. If it were desired to run only 10 
hours a day and to operate 15 days a month a pump capacity of 720 
gallons per minute (80 miner's inches) would be required. For the 
usual sandy soil on which alfalfa is grown in San Diego County it 



TESTS OF PUMPING PLANTS. 281 

would probably be found best to put on only a 3 or 4 inch depth of 
water at each irrigation and to use a head as large as would be 
economically feasible. A good practice would be to irrigate twice 
a month with about 3 inches each time, each irrigation period lasting 
twelve 10-hour days, the six days interveinng between successive 
irrigating periods being used for making any needed repairs to the 
plant. On this schedule of irrigation a pump capable of supplying 
450 gallons per minute (50 miner's inches) would be required. Such 
a pump would furnish a stream large enough to be used economically 
with the common method of irrigation by portable pipes. 

The size of pump of the type selected must be determined from a 
study of the manufacturers' catalogues. In selecting the size of 
pump the fitness of the pump for the conditions of head and discharge 
under which it is to operate should be carefully considered. As a 
rule, each manufacturer makes only one size of stock pump that 
will give the highest efficiency when operating under the given 
conditions of head and discharge, and this pump must be run at the 
one speed corresponding to the head pumped against. The kind of 
power and the manner of connection between pump and motor 
must also be borne in mind, as either may limit the speed at which 
the pump is to operate. Thus, if a centrifugal pump is to be direct- 
connected to a motor, a pump must be selected which will operate at 
the high speed at which motors generally run and which will at the 
same time give a high efficiency under the given conditions of dis- 
charge and head; if the pump is to be belt-connected to a gasoline 
engine, one run at a lower speed would probably be best suited to 
the conditions. 

TYPE OF PTTMP. 

Classification of types. — The required capacity of the pump having 
been determined, the type of pump must next be selected. Although 
pumps of many types are used for pumping water for irrigation, three 
main types, which will cover all combinations of conditions, have 
been found most suitable — the centrifugal pump, the power plunger 
or piston pump, and the deep-well reciprocating pump. Rotary 
pumps of certain types are used in a few plants but are adapted only 
for pumping water that is clean and free from sand. Air lifts are 
feasible only for large plants and, because of their low efficiency, 
should be used only under special conditions; they are not suited for 
use in small pumping plants for irrigation. 

Each of these types of pumps is particularly adapted to a certain 
set of conditions, the limits of which are well recognized, notwith- 
standing the fact that some manufacturers of' pumps of one special 
type may claim that their pump is suitable for use under all condi- 
tions, without regard to economy in operation, capacity, head, or 
practical difficulties of operation. 



282 

Power plunger pumps. — Power plunger pumps, either duplex or 
triplex, are adapted to pumping small quantities of water, usually 
less than 150 to 200 gallons per minute, against heads exceeding 75 
feet, where the depth of water in the well below the ground surface 
during pumping does not exceed about 25 feet. For such conditions 
the cost of fuel or electricity used for pumping is relatively small 
and the plunger pumps are more efficient than centrifugal pumps of 
such small capacity. The first cost of the plunger pump per unit 
capacity is high compared to that of centrifugal pumps. If a capacity 
much over 200 gallons a minute is required the advantage of cheaper 
fuel or electricity may be more than offset by the higher fixed charges 
on the first cost, and hence a centrifugal pump of lower first cost per 
unit capacity may become cheaper. Again, in order that it may be 
within suction lift of the water level, it is usually necessary to set a 
pump of this type in an open pit; therefore if the depth to water 
level becomes much greater than 25 feet, the first cost of the pit 
may offset the cheaper cost of fuel or electricity, and a vertical 
centrifugal pump, or perhaps a deep-well centrifugal pump, inclosed 
in a steel casing may become cheaper on account of lower total first 
cost. The economical capacity of the power plunger pump is usually 
too small for irrigation of alfalfa and is best adapted to irrigating 
small orchards or truck gardens. 

Deep-well reciprocating pumps. — Deep-well reciprocating pumps are 
adapted to pumping small quantities of water, usually not more than 
200 or 300 gallons a minute, from depths ranging from 100 to 400 feet 
below the surface of the ground. Under such conditions a pump of 
this type is more efficient than a centrifugal pump and the cost of 
fuel or electricity is less. However, the first cost of this pump is 
high per unit capacity as compared with that of the centrifugal pump, 
and hence, if the required capacity is much more than 200 gallons a 
minute, a vertical centrifugal deep-well pump inclosed in a steel 
casing may be found cheaper, on account of a smaller first cost. 
Most pumps of this type are too small for economical irrigation of 
alfalfa and they are best adapted to the irrigation of small orchards 
or truck gardens. 

Centrifugal pumps. — The centrifugal pump in its various forms has 
an adaptability wider by far than that of pumps of any other type 
and it is more commonly used for pumping water for irrigation than 
all other types together. It is adapted to pumping water in quantities 
ranging from 20 to several thousand gallons per minute, against 
heads ranging from a few feet to several hundred feet. Except where 
it is required to pump small quantities of water — up to 200 or 300 
gallons a minute — either from depths below the ground surface of 
at least 100 feet or to heights above the ground surface of more than 
75 feet, some form of centrifugal pump will usually be found cheapest 



TESTS OF PUMPING PLANTS. 283 

and best to install and operate. The centrifugal pump must always 
be placed within easy suction lift of the water level in the well, care 
being taken to allow for the drawdown of the water level in the 
well during pumping as well as for natural fluctuations of the ground- 
water level. In practice the suction lift should never exceed 20 feet 
and it should preferably be less. 

In general, where conditions are such that either a vertical or a 
horizontal centrifugal pump can be used, the horizontal is to be pre- 
ferred because of its higher efficiency and more perfect running con- 
ditions. The horizontal form can ordinarily be used only where the 
water level in the well is not more than 40 feet below the surface and 
where its fluctuations during the season are small. In pumping 
from wells where the depth to water is so great that the pump must 
be placed in a pit more than 25 feet deep, or where there is a large 
fluctuation in the water level, or where both these conditions occur 
^together, the vertical form of centrifugal pump is best adapted. 
The vertical form requires a smaller pit than the horizontal form, and 
the motor or engine and belt connection, if used, are on the surface of 
the ground, so that the pump may be run submerged. Even if the 
depth to the water were less than 40 feet, if fluctuations in water 
level were large the successful operation of a horizontal centrifugal 
pump might require that it be placed in a water-tight concrete pit 
to keep the motor or the belt from becoming wet. The expense and 
difficulty of constructing such a water-tight pit might therefore make 
the use of the vertical form more desirable. The open-pit type of 
vertical centrifugal pump should not be used where the depth to 
ground-water level during pumping exceeds 75 feet. 

Single-stage centrifugal pumps, especially designed and driven at 
a sufficiently high rate of speed, may be used to pump against total 
heads considerably more than 100 feet, but usually the stock pump 
obtainable from the manufacturers is not suitable for heads greater 
than 75 feet for the large sizes and 50 feet for the smaller sizes. For 
greater heads compound or multi-stage centrifugal pumps are used, 
allowing 75 to 125 feet head for each stage. 

During the last few years a new form of vertical centrifugal pump, 
commonly called the turbine or deep-well centrifugal pump, has been 
devised for pumping from deep wells without the necessity of a pit. 
It is similar in form to the multi-stage pump except that the diameter 
of runner is generally made smaller, 12 to 30 feet of head being allowed 
for each stage, the lower limit corresponding to the smaller capacities. 
As the pump is always placed below the water level and run submerged 
no priming is necessary. The pump parts and vertical shafting 
jare installed inside a steel casing 12 to 30 inches in diameter, and 
^this casing, which is usually larger than the well casing, is connected 
to the well casing just below the bottom stage of the pump. Power 



284 

is supplied above the ground surface. Pumps of this type are adapted 
to pumping quantities of water ranging from 200 to 2,000 gallons or 
more a minute from depths ranging from 75 feet to 400 feet below the 
surface of the ground. Many defects in the original design and op- 
eration of centrifugal pumps of this form have been remedied b] 
the manufacturers, and pumps of the larger capacities — 900 to 1,00( 
gallons a minute — are now giving efficiencies as high as 70 per cenl 
Where the water level is more than 250 feet below the surface 
the ground serious difficulties are still involved in the operation 
pumps of this design. The hydraulic down thrust on the pump run- 
ners, which it is difficult and usually impracticable to balance hy- 
draulically in a centrifugal pump of this form, is taken up by the 
support bearing in the pump head at the ground surface, from which 
the pump and shafting are suspended. This method creates a 
tensional stress in the vertical shaft, which is thereby -elongated, 
and with long shafts and large pumps the elongation may become so 
great as to close up the clearance space allowed between the pump 
runners and casing and thus make operation impossible. Only 
the smaller sizes of pumps of this form, capable of furnishing not 
more than about 500 gallons a minute, seem at present adapted to 
use in wells in which the water level is 300 or 400 feet below the sur- 
face of the ground. Such pumps are now being used in many wells 
under conditions for which the ordinary form of vertical centrifugal 
pump was formerly considered best suited. The deep-well centrif- 
ugal pump is also used to advantage in getting a maximum yield 
from a poor well by placing the pump far below the water level in 
the well, thus allowing a much greater drawdown than would ordi- 
narily be possible with a -pump of any other type. 

POWER. 
TYPE OF POWER. 

The choice of power for small irrigation pumping plants will usu- 
ally lie between the internal combustion engine and the electric 
motor. In the last few years a modified form of the gasoline engine 
and a few special types of internal combustion engines have been 
developed which are capable of using the heavier distillates. Some 
of these engines have proved very successful and are of great value 
because of their use of cheap fuel. The cost of power in gasoline- 
engine plants and in motor-driven plants varies locally with the price 
of gasoline and of electric power. It must be borne in mind, how- 
ever, that the cost of power is not the only matter to be considered. 
Motors are cheaper in first cost per unit horsepower, depreciate less 
rapidly, are more efficient, and are more convenient to operate than 
gasoline engines. A gasoline engine may cost but little (though 
this is somewhat uncertain) for attendance if kept in good running 



TESTS OF PUMPING PLANTS. 285 

order, whereas a motor generally costs little for attendance and 
repairs. 

If a gasoline engine is selected care should be taken to install only 
one made by a reliable manufacturer. The cheaper engines are not 
only flimsy and weak in certain parts but they are also overrated, 
that is, rated at a horsepower which they can attain only at speeds 
that are so high as to cause excessive depreciation. The speed of 
an engine of 6 horsepower or less should not exceed 300 revolutions 
per minute; for sizes above 6 horsepower the speed should decrease 
to 200 revolutions per minute or less. 

SIZE OF ENGINE OR MOTOR. 

The size of the engine or motor depends on the quantity of water to 
be pumped, the total head to be pumped against — which must in- 
clude not only the static head but the head due to losses by friction 
in the discharge and suction pipes — and the efficiency of the pump. 

The water horsepower must first be computed as the product of 
the quantity of water pumped, in gallons per minute, by the weight 
of a gallon of water in pounds (1 gallon of water weighs 8.34 pounds), 
by the total head in feet, divided by 33,000. The horsepower input 
necessary at the pump is then obtained by dividing this water horse- 
power by the pump efficiency. The efficiency of the pump should 
be determined from an actual test of the pump, and the high estimates 
of efficiency made by some manufacturers should be accepted with 
caution. 

Motors and gasoline engines are rated on brake horsepower. If 
the motor or engine is direct-connected to the pump, the input at 
the pump will be the required brake horsepower of the motor or 
engine; if the motor or engine is connected to the pump by belt, 
chain, or gear, the required brake horsepower must be determined 
by dividing the input at the pump by the estimated efficiency of the 
transmission. It will usually be safe to estimate the efficiency of 
belt transmission at 90 to 95 per cent. 

PIPING AND CONNECTIONS. 

There are many seemingly unimportant details in connection with 
the installation of pumping machinery which, if neglected, cause 
needless loss of energy and increase in cost of pumping. Many 
pumping plants give low efficiency simply because of defects in such 
details. 

In general, the more direct the connection between the pump and 
engine or motor the better. For motor-driven plants the ideal 
method of applying power to the pump is by direct connection be- 
tween motor and pump, as it eliminates the loss of power, more or 
less large, which is always involved in indirect transmission. Al- 



286 GKOUlND WATEKS OF WESTEKN SAN DIEGO COUNTY, CALIF. 

though this method is not always feasible, it should be adopted wher- 
ever possible. If belt transmission between pump and motor or 
engine is used the loss in power should be made as small as possible 
by decreasing the amount of slippage in the belt. The pulleys ordi- 
narily found on centrifugal pumps are so small that it is impossible 
to prevent undue slippage. Larger pulleys than are usually fur- 
nished for both pump and motor should be specified in ordering, say, 
not less than a 12-inch pulley on a 4-inch pump. It is, of course, 
necessary to have the pulleys on pump and motor of the proper pro- 
portionate size so as to insure proper speed of both motor and pump. 
Idler pulleys and countershafts should be avoided, as they increase 
the loss in power. The belt connection should be not less than 16 
feet center to center of pulleys. 

The foot valves installed in many pumping plants at the bottom 
of the suction pipe usually interfere very materially with the flow of 
water into the pipe, and their use should be avoided. In their stead 
a check valve should be used, placed immediately above the discharge 
opening of the pump, or, better still, a flap valve which can be lowered 
over the upper end of the discharge pipe, as in this way the pump can 
be quickly primed before starting by means of an ordinary pitcher 
pump connected to the top of the pump casing. 

The suction and discharge pipes should be materially larger than 
the pump openings. The loss in friction depends on the size of the 
pipe. Doubling the diameter of the pipe, other things being equal, 
reduces the internal friction head in the pipe to one thirty-second of 
its former value and reduces the head lost in discharge to one-sixteenth 
of its former value. The size of pipe should be at least 1 inch 
larger for sizes of pump less than 4 inches. The losses at entrance to 
the suction and exit from the discharge pipes may be greatly reduced 
by installing a tapering pipe at the ends thereof, of a length about 
two and one-half times the diameter of pipe, and gradually increasing 
the diameter of the pipe to about one and three-fourth times at the 
end. The pipe should have as few bends as possible, and sharp 
bends and turns in the piping should be avoided. All elbows and 
tees should be of the "long-sweep" form, which may be obtained 
from the regular stock of the larger dealers at no greater cost than 
the fittings with sharp bends. 



GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 287 

CONVENIENT EQUIVALENTS. 

The following list and tables of equivalents will be found convenient 
for use in hydraulic computations. 

Table 62. — Conversion table — Rates offow. 



Cubic feet 

per 

second. 


Miner's 
inches 
(south- 
ern Cali- 
fornia, 
stand- 
ard). 


U.S. 
gallons 

per 
minute. 


Acre-feet 

per day 

of 24 

hours. 


Acre-feet 

per year 

of 365 

days. 


U. S. gallons 

per day of 24 

hours. 


1 
.02 

.002,228 
.504 
.001,38 
1.547 


50 
1 

.1114 
25.21 

.0691 
77.36 


448.83 
8.976 
1 

226. 29 
.62 

694.44 


1.9835 
.0397 
.00442 

1 
.00274 

3.07 


723.97 
14.48 
1.613 
365 
1 
1, 120. 14 


646,317 

12,926 

1,440 

325,851 

890 

1,000,000 



Table 63. — Conversion table — Pressure units. 



Pounds 

per 
square 
inch. 


Inches 

of 

mercury. 


Feet of 
water. 


1 

.4910 
.4333 


2.037 

1 
.8826 


2.308 
1.133 
1 



1 cubic foot of water weighs 62.4 pounds. 

1U. S. gallon of water weighs 8.34 pounds. 

1 cubic foot equals 7.48 U. S. gallons. 

1 acre-foot equals 43,560 cubic feet, equals 325,851 U. S. gallons. 

1,000,000 cubic feet equal 22.95 acre-feet. 

1 second-foot equals 50 miner's inches (southern California standard). 

1 second-foot equals 40 miner's inches (California statute). 

1 second-foot equals about 1 acre-inch per hour. 

1 horsepower equals 0.746 kilowatts. 

1 kilowatt equals 1.34 horsepower. 



Water horsepower equals 



second-feet of water X 62.4 X total head in feet 



550 



gallons of water per minute X 8.34 X total head in feet 
or 33,000 

Required brake horsepower of motor or engine equals 

water horsepower 



efficiency of pump X efficiency of transmission. 



288 GKOUOT WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 
PUBLICATIONS CONSULTED. 

PHYSIOGRAPHY, GEOLOGY, AND GROUND WATER. 

Blake, W. P., Geological report, explorations, and surveys for a railroad route from 
the Mississippi River to the Pacific Ocean: 33d Cong., 2d sess., S. Doc. 78, pp. 
122-130, 176, 1856. 

Observations on the physical geography and geology of the coast of California 

from Bodega Bay to San Diego: IT. S. Coast Survey Rept. 1855, pp. 376-398, 1856. 

Clark, W. 0., Ground-water resources of Niles cone and adjacent areas, Calif.: U. S. 

Geol. Survey Water-Supply Paper 345-H, 1915. 
Conrad, T. A., Description of Cretaceous and Tertiary fossils: United States and 

Mexican Boundary Survey, vol. 1, pt. 2, 1857-1859. 
Emory, W. H., Notes: United States and Mexican Boundary Survey, vol. 1, pt. 2, 

1857-1859. 
Fairbanks, H. W., Geology of San Diego County; also portions of Orange and San 

Bernardino counties: California State Min. Bur., vol. 11, pp. 76-120, 1892. 

The physiography of California: Amer. Bur. Geog. Bull., vol. 2, pp. 232-252, 

329-353, 1901. Reprinted separately. 

Hilgard, E. W., Subterranean water supply of the San Bernardino Valley: U. S. 

Dept. Agr. Office Exper. Sta. Bull. 119, p. 103, 1902. 
Goodyear, W. A., San Diego County: California State Min. Bur., vol. 8, pp. 516-528, 

1887-88. 
Hall, James, Paleontology and geology of the boundary: United States and Mexican 

Boundary Survey, vol. 1, pt. 2. 
Kinney, Abbot, Forest and water, with articles on allied subjects by eminent experts, 

250 pp., 53 illus., 1900. 
Lee, C. H., An intensive study of the water resources of a part of Owens Valley, Calif. 

U. S. Geol. Survey Water-Supply Paper 294, 1912. 

Subterranean storage of flood water by artificial methods in San Bernardino 

Valley, Calif.: California State Conservation Commission Rept. 1912. 

Ground-water resources of Indian Wells Valley, Calif.: California State Con- 
servation Commission Rept. 1912. 

The determination of safe yield of underground reservoirs of the closed basin 



type: Am. Soc. Civil Eng. Trans., vol. 78, p. 148, 1915. 

Meinzer, O. E., Ground water in Big Smoky Valley, Nev.: U. S. Geol. Survey 
Water-Supply Paper 375-D, 1916. 

Meinzer, O. E., and Hare, R. F., Geology and water resources of Tularosa basin, 
N. Mex.: U. S. Geol. Survey Water-Supply Paper 343, 1915. 

Meinzer, O. E., and Kelton, F. C, Geology and water resources of Sulphur Springs 
Valley, Ariz: U. S. Geol. Survey Water-Supply Paper 320, 1913. 

Mendenhall, W. C, Development of underground waters in the eastern coastal- 
plain region of southern California: U. S. Geol. Survey Water-Supply Paper 137, 
1905. 

Development of underground waters in the central coastal-plain region of 

southern California: U. S. Geol. Survey Water-Supply Paper 138, 1905. 

Hydrology of San Bernardino County, Calif.: U. S. Geol. Survey Water- 
Supply Paper 142, 1905. 

Ground waters and irrigation enterprises in the foothill belt, southern Cali- 



fornia: U. S. Geol. Survey Water-Supply Paper 219, 1908. 
Mendenhall, W. C, Dole, R. B., and Stabler, Herman, Ground water in San 

Joaquin Valley, Calif.: U. S. Geol. Survey Water-Supply Paper 398, 1916. 
Merrill, F. J. H., Geology and mineral resources of San Diego and Imperial counties: 

California State Min. Bur., 1914. 



PUBLICATIONS CONSULTED. 289 

Newberry, J. S., Geological Report: In Report upon the Colorado River of the West, 

explored in 1857 and 1858 by Lieut. J. C. Ives under the direction of the Office of 

Explorations and Surveys: 36th Cong., 1st sess., H. Doc. 90, pp. 13-18, 1861. 
Orcutt, C. R.' [Notes on the geology of San Diego County]: West American Scientist, 

vol. 2, p. 32, April, 1886; vol. 3, p. 124, May, 1887; vol. 6, p. 15, April, 1889; vol. 
, 6, p. 84, August, 1889; vol. 7, p. 24, July, 1890; vol. 10, p. 17, February, 1900; 

vol. 12, p. 2, June, 1901. 
Parry, C. C, and Schott, Arthur, Geological reports: United States and Mexican 

Boundary Survey, vol. 1, pt. 2, 1857-1859. 
Slichter, C. S., The motions of underground waters: U. S. Geol. Survey Water-Supply 

Paper 67, 1902. 
Field measurements of the rate of movement of underground waters: U. S. 

Geol. Survey Water-Supply Paper 140, 1905. 
Underflow of Arkansas Valley in Western Kansas: U. S. Geol. Survey Water- 



Supply Paper 153, 1906. 
Smith, G. E. P., Ground-water supply and irrigation in the Rillito Valley: Arizona 

Univ. Agr. Exper. Sta. Bull. 64, 1910. 
The utilization of ground waters by pumping for irrigation: International Eng. 

Cong. Trans., Paper 37, 1915. 
Spear, W. E., An additional supply of water for the city of New York from Long 

Island sources: Board of Water Supply of City of New York Rept., vols. 1 and 2, 

1912. 
Van Dyke, J. C, The desert: Further studies in natural appearances, 233 pp., 1901. 
Van Dyke, T. S., County of San Diego, the Italy of southern California. 1887. 
San Diego County, Calif., written for the San Diego Chamber of Commerce, 

1890. 
The underground waters of southern California, in Forest and water, by Abbot 

Kinney. 
Veatch, A. C, Fluctuations of the water level in wells, with special reference to Long 

Island, N. Y. : U. S. Geol. Survey Water-Supply Paper 155, 1906. 

PUMPING PLANTS. 

Bowie, A. J., jr., Practical irrigation, McGraw-Hill Book Co., 1908. 

Bryan, Kirk. Ground water for irrigation in the Sacramento Valley, Calif.: U. S. 
Geol. Survey Water-Supply Paper 375-A, pp. 37-43, 1915. 

Clapp, F. G., Underground waters near Manassas, Va.: U. S. Geol. Survey Water- 
Supply Paper 258, pp. 102-108, 1911. 

Darton, N. H., Underground water of Luna County, N. Mex.: U. S. Geol. Survey 
Water-Supply Paper 345-C, 1914. (Results of pumping tests, by A. T. Schwen- 
nesen, pp. 37-40.) 

Etcheverry, B. A., Irrigation practice and engineering, vol. 1, 1st ed., McGraw- 
Hill Book Co., 1915. 

Fleming, B. P., Practical irrigation and pumping, 1st ed., John Wiley & Sons., 1915. 

Fleming, B. P., and Stoneking, J. B., Tests of pumping plants in New Mexico, 
1908-09: New Mexico Coll. Agr. and Mechanic Arts, Agr. Exper. Sta. Bull. 73, 
1909. 

Tests of centrifugal pumps: New Mexico Coll. Agr. and Mechanic Arts, Agr. 

Exper. Sta. Bull. 77, 1911. * 

Gregory, W. B., Mechanical tests of pumps and pumping plants: U. S. Dept. Agr., 
Office Exper. Sta. Bull. 183, 1907. 

— The selection and installation of machinery for small pumping plants: U. S. 

Dept. Agr. Office Exper. Sta. Cir. 101, 1910. 

Cost of pumping from wells for irrigation of rice in Louisiana and Arkansas: 

U. S. Dept. Agr. Office Exper. Sta. Bull. 201, 1908. 
115536°— 19— wsp 446 19 



290 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Le Conte, J. N., Mechanical tests of pumping plants used for irrigation: U. S. Dept. 

Agr. Office Exper. Sta., Bull. 158, pp. 192-255, 1905. 
Le Conte, J. N., and Tait, C. E., Mechanical tests of pumping plants in California: 

U. S. Dept. Agr. Office Exper. Sta. Bull. 181, 1907. 
Meinzer, O. E., and Kelton, F. C, Geology and water resources of Sulphur Spring 

Valley, Ariz.: U. S. Geol. Survey Water-Supply Paper 320, pp. 187-213, 1913. 
Slichter, C. S., Theoretical investigation of the motion of ground water: U. S. 

Geol. Survey Nineteenth Ann. Rept., pt. 2, pp. 295-384, 1899. 
The motions of underground waters: U. S. Geol. Survey Water-Supply Paper 

67, 1902. 
Field measurements of the rate of movement of underground waters: U. S. 

Geol. Survey Water-Supply Paper 140, 1905. 

Observations on the ground waters of the Rio Grande valley: U. S. Geol. 

Survey Water-Supply Paper 141, pp. 31-73, 1905. 

The underflow in Arkansas Valley in western Kansas: U. S. Geol. Survey 

Water-Supply Paper 153, pp. 55-87, 1906. 

Smith, G. E. P., Pumping plants for irrigators: Arizona Univ. Agr. Exper. Sta. Bull. 
60, pp. 399-411, 1909. 

Ground-water supply and irrigation in the Rillito Valley: Arizona Univ. 

Agr. Exper. Sta. Bull. 64, pp. 201-222, 1910. 

Oil engines for pump irrigation and cost of pumping: Arizona Univ. Agr. Exper. 



Sta. Bull. 74, pp. 439-450, 1915. 
Tait, C. E., The use of underground water for irrigation at Pomona, Calif.: U. S 
Dept. Agr. Office Exper. Sta. Bull. 236 (revised), pp. 43-55, 1912. 



DETAILED PRECIPITATION RECORDS. 

Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County. 

[For summary of records see Table 17, p. 79. All the means were computed by C. H. Lee.] 

Warner dam site (1) : elevation, 2,702 feet. 

[Authority, Volcan Land & "Water Co., W. S. Post, engineer.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1911-12 


0.87 
.15 
.47 

2.04 

.88 


0.00 

.68 
.88 
.00 

.39 


0.39 
.00 
.15 
.06 

.02 


0.37 

2.77 

.23 

.76 

1.03 


0.13 
1.49 
3.64 
1.13 

1.59 


1.98 

.08 

1.70 

5.07 

2.21 


0.71 

3.79 
10.71 
11.15 

6.58 


0.05 

7.67 
8.05 
11.22 

6.75 


15.60 
1.58 
3.10 
2.30 

5.62 


4.68 

.83 

2.54 

6.67 

3.68 


1.34 
.30 
.09 

3.23 

1.24 


0.19 
.24 
.21 

.07 

.18 


26.31 


1912-13 

1913-14 

1914-15 


19.58 
31.77 
43.70 


4-year means 


30.34 



Damrons (2) ; elevation, 2,725 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1911-12 

1912-13 


a0.45 
.03 
.34 

.44 

.32 


0.00 

.27 

3.19 

.00 

.87 


0.16 
.00 
.34 
.00 

.13 


0.20 

2.20 

.06 

.25 

.68 


0.07 
2.52 
4.11 
1.32 

2.01 


1.81 

.02 

2.01 

6.33 

2.54 


0.67 
3.78 
11.51 
11.14 

6.78 


Tr. 
9.12 
7.96 
13.89 

7.74 


16.08 

3.62 

2.08 

.93 

5.68 


4.94 
1.14 
2.71 
6.60 

3.85 


1.47 
.44 
.12 

5.40 

1.86 


0.30 
.32 
.54 
.09 

.31 


26.15 
23.46 


1913-14 


34.97 


1914-15 

4-year means 


46.39 
32.74 



Monkey Hill (3); elevation, 2,810 feet. 

[Authority, Volcan Land & Water Co.] 



1911-12 


o0.50 
.40 
.46 
.56 

.49 


0.00 

a. 40 

1.84 

.00 

.56 


0.30 
.00 

.05 
.00 

.09 


0.14 

1.92 

.08 

.59 

.68 


Tr. 

.60 
1.37 
1.21 

.79 


0.69 

.00 

1.05 

3.33 

1.27 


0.28 
1.60 
5.21 
7.21 

3.58 


Tr. 

3.86 
3.96 
5.05 

3.22 


6.03 
.30 

1.28 
.45 

2.02 


2.19 

.33 

1.06 

3.16 

1.69 


1.37 
.05 
.00 

.74 

.54 


0.18 
.17 
.09 
.04 

.12 


11.68 


1912-13 

1913-14 


9.63 
lb. 45 


1914-15 

4-year means 


22.34 
15.03 



a Estimated. 



DETAILED PRECIPITATION RECORDS. 



291 



Table 64. — Monthly and annual precipitation^ at 106 stations in or near San Diego 

County — Continued. 

Warner summer road (4) ; elevation, 2,805 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1911-12 


o0.50 
.50 
.34 
.93 

.57 


0.00 
.42 

1.44 
.00 

.47 


0.35 
.00 
.02 
.00 

.09 


0.14 

2.04 

.06 

.66 

.73 


0.07 

.79 

1.79 

1.47 

1.03 


0.83 

.38 
.89 

2.87 

1.24 


0.46 
2.45 
6.77 
8.01 

4.42 


Tr. 
3.97 
5.18 
7.28 

4.11 


8.48 
.79 

1.27 
.50 

2.76 


2.80 

.35 

1.41 

4.77 

2.33 


1.43 
.08 
.00 

1.21 

.68 


0.20 
.16 
.14 
.06 

.14 


15.26 


1912-13 

1913-14 


11.93 
19.31 


1914-15 


27.76 


4-year means 


18.57 



Puerta La Cruz (5) ; elevation, 2,772 feet. 
[Authority, Voican Land & Water Co., W. S. Post, engineer.] 



1911-12 


a0.50 
.20 
.41 
.56 

.42 


0.00 
.53 

1.47 
.00 

.50 


0.23 
.00 
Tr. 
Tr. 

.06 


0.15 

2.11 

.12 

.63 

.75 


0.12 
.50 

1.48 
.98 

.77 


0.98 

.02 

.75 

4.14 

1.47 


0.23 
2.42 
6.42 
7.62 

4.17 


Tr. 
3.97 
5.25 
7.03 

4.06 


7.82 
1.17 
1.20 

.48 

2.67 


2.85 

.40 

2.21 

5.43 

2.72 


1.05 
.06 
.00 

1.12 

.56 


0.27 
.15 
.21 
.07 

.18 


14.20 


1912-13 


11.53 


1913-14 


19.52 


1914-15 


28.06 


4-year means 


18.33 



Deadmans Hole (6); elevation, 3,200 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1911-12 

1912-13 

1913-14 

1914-15 

■4-year means 



o0.75 


0.00 


0.65 


0.20 


Tr. 


1.20 


0.21 


0.05 


9.81 


3.48 


1.54 


0.17 


.15 


.58 


.00 


1.73 


.61 


.00 


1.50 


5 77 


1.18 


.50 


.10 


.07 


.33 


2.13 


.04 


.05 


2.46 


1.09 


7.42 


6.79 


1.76 


1.59 


.06 


.09 


.06 


.04 


.05 


.57 


.94 


4.45 


9.64 


8.26 


2.44 


4.28 


1.62 


.10 


.11 


.83 


2.46 


3.80 


5.22 


4.69 


1.69 


1.00 


.64 


.19 


.69 


.32 



18.06 
12.19 
23.81 
32.45 

21.63 



Pamo (7); elevation, 1,050 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1911-12 

1912-13 

1913-14 

2-year means . 



a0.75 
.04 
.26 


0.00 
.20 
.00 


0.46 

.09 
.06 


0.32 

2.08 
.35 


0.11 
1.25 
3.21 


1.37 

.10 

1.47 


0.70 
2.14 


0.00 
4.71 
(*) 


9.21 
1.79 

(6) 


3.67 
.95 


1.97 
.22 
(*) 


0.14 
.16 


.39 


.10 


.27 


1.20 


.68 


.74 


1.42 


2.26 


5.50 


2.31 


1.09 


.15 



18.70 
13.73 
-(b) 

16.21 



Santa Ysabel ranch (8) ; elevation, 3,000 feet. 

[Authorities: 1900 to 1910-11, S. Rotanzi; 1911-1915, Volcan Land & Water Co., W. S. Post, engineer.] 



1900-1901 




! I 












1 




21.45 


1901-2 




! ■ 1 
















18.65 


1902-3 
























20 75 


1903^ 
























11.00 


1904-5 

























31.00 


1905-6 
























42 00 


1906-7 
























24 70 


1907-8 




















1 




24 00 


1908-9 




















1 




25.25 


1909-10 
























22 85 


1910-11 



























o20 00 


1911-12 

1912-13 


a0.35 

2.50 

.38 

.00 

.81 


0.00 
.50 
.75 
.00 

.06 


0.60 
.00 
.00 
.05 

.16 


0.45 

3.50 

.00 

1.74 

1.42 


a0.30 
1.75 
3.47 
1.05 

1.64 


1.85 

.05 
2.44 
4.41 

2.19 


1.10 
2.95 
8.25 
10.70 

5.75 


0.10 
2.57 
6.00 
9.00 

4.42 


12.25 
3.20 
1.40 
3.45 

5.08 


4.05 
1.25 
3.29 
7.00 

3.90 


1.85 
.55 
.00 

1.80 

1.05 


0.32 
.50 
.90 
.00 

.43 


23.22 
19.32 
26.88 
39.20 

24.68 


1913-14 

1914-15 

4-year means 



a Estimated. 



b Abandoned; see No. 63, 2 miles south of Volcan Land & Water Co. 



292 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued. 

Santa Ysabel Store (9); elevation, 2,983 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1911-12 


a0.35 

.00 

.69 

1.20 

.56 


0.00 
.60 

.78 
.00 

.45 


a0.60 
.00 
.00 
Tr. 

.15 


a0.45 

3.70 

.00 

1.59 

1.44 


a0.30 

al.75 

3.06 

1.28 

1.60 


2.05 

a .05 

2.03 

3.70 

1.96 


1.15 

a2.95 
8.48 
8.63 

5.30 


Tr. 

a2.57 
6.25 
10.38 

4.80 


13.97 

a3.20 

1.51 

2.68 

5.34 


4.12 

al.25 

2.53 

5.43 

4.44 


2.00 

a .55 

.00 

5.98 

2.13 


0.35 

a .50 

a .90 

.00 

.44 


25.34 
17.12 
26.23 
40.87 

27.39 


1912-13 


1913-14 


1914-15 

4-year means 



Witch Creek (10); elevation, 2,800 feet. 

[Authority, J. Woods.] 



1909-10 


























25.40 
23.55 
26.24 
20.25 
27.30 
40.40 

27.19 


1910-11 


























1911-12 


a0.35 

.15 
.30 
.00 

.20 


0.00 
.60 
.40 
.00 

.25 


0.64 
.00 
.00 
.10 

.19 


0.65 

4.00 

.00 

1.30 

1.49 


0.35 

1.60 

3.90 

.90 

1.69 


2.00 

.00 

2.40 

5.40 

2.45 


1.40 
3.50 
8 80 
9.75 

5.86 


0.00 
6.05 
6.25 
10.30 

5.65 


14.20 
2.55 
1.45 
2.30 

5.13 


4 95 

.75 

3.10 

6.00 

3.70 


1.40 
.55 
.00 

4.35 

1.58 


0.30 
.50 
.70 
.00 

.38 


1912-13 


1913-14 


1914-15 


4-year means 


[Authorities: 1896 to 


1910-1 


Ram 

1, R. ] 


ona (Verlaqu 

->. Verlaque; 


e) (11); elevation, 
1911-1915, Volcan L 


1,440 feet. 

and & Water Co., W. S. Post, engineer. 


1896-97 


0.00 

.00 
.00 
.00 
.00 
.00 
.25 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
a .20 
.00 
.20 
.00 


0.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.25 
.00 
.00 

1.10 
.00 
.00 
.33 
.00 
.00 


0.00 
.00 
.00 
.00 
.00 
.00 
.00 
.15 
.00 
.32 
.30 
.00 
.30 
.00 
.00 
.45 
.00 
.00 
.00 


1.95 

1.55 
.00 
.75 
.00 
.40 
.20 
.35 
.55 
.20 
.20 

3.59 
.45 
.00 

1.05 
.28 

1.35 
.55 

1.15 

.77 


1.37 

.00 

.75 

1.50 

3.55 

.37 

2.30 

.00 

.00 

5.50 

2.25 

.45 

.65 

3.85 

1.55 

.00 

.80 

2.60 

1.45 


1.90 

.96 

1.10 

1.25 

.00 

.10 

2.25 

.00 

2.30 

1.13 

5.42 

1.10 

1.30 

7.30 

.40 

1.75 

.00 

1.50 

3.10 

1.73 


4.93 
3.25 
2.80 
4.85 
2.15 
2.35 
1.45 

.32 
4.70 
2.30 
5.75 
5.04 
7.45 
3.25 
5.25 

.75 
2.30 
7.85 
8.65 

3.96 


5.93 
.25 

1.05 
.15 
6.10 
2.83 
3.60 
2.26 
9.82 
4.17 
1.28 
3.96 
4.85 
.55 
5.60 
.00 
4.79 
4.75 
6.95 


2.88 

1.95 

1.35 

.85 

.50 

3.50 

2.51 

4.25 

7.98 

11.80 

3.49 

1.92 

3.05 

2.07 

1.75 

9.80 

1.40 

.75 

.97 

3.31 


0.00 
.00 
.00 

1.80 
.00 
.80 

3.70 
.63 

1.13 

2.10 
.53 
.77 
.00 
.45 

1.35 

4.02 

.20 

a2.02 

4.36 

1.25 


0.00 

1.35 

.00 

1.90 

1.42 

.00 

.35 

.35 

2.12 

1.13 

.52 

.47 

.00 

.00 

.00 

1.85 

.37 

.30 

2.65 

.76 


0.00 

.00 
1.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.25 
.00 
.00 
.00 
.00 
.20 
.30 
.00 
.00 

.09 


18.96 
9.31 
8.05 
13.05 
13.72 
10.35 
16.61 
8.31 
28.60 
28.65 
20.24 
17.30 
18.05 
18.57 
16.95 
19.30 
11.84 
20. 52 
29.28 

17.25 


1897-98 


1898-99 


1899-1900 


1900-1901 

1901-2 


1902-3 


1903-4 


1904-5 


1905-6 


1906-7 


1907-8 

1908-9 


1909- 10 


1910-11 


1911-12 


1912-13 

1913-14 


1914-15 


19-year means 






Ram 


ona (Sentinc 

Authority, I 


1) (12); elevation, 

teed, Sentinel news 


1,440 1 

paper.; 


eet. 






1911-12 


a0.20 
.00 

a .20 
.00 

.10 


0.00 
.40 
.00 
.00 

.10 


a0.40 
.00 
.15 
Tr. 

.14 


a0.25 

1.35 

.50 

1.01 

.78 


0.00 
.32 

2.85 
1.34 

1.13 


1.52 

.00 

1.20 

3.15 

1.47 


0.67 
1.85 
6.35 
6.78 

3.91 


0.00 
4.50 
3.87 
o7.00 

3.84 


8.62 
.37 
.60 

1.30 

2.72 


3.75 

a .20 

2.02 

4.97 

2.73 


2.03 

a .37 

.62 

1.89 

1.23 


Tr. 

a .30 
.23 
.00 

.13 


17.44 

9.66 

18.59 

27.44 

18.28 


1912-13 


1913-14 


1914-15 


4-year means 



Rose Glen (13) ; elevation, 2,300 feet. 

[Authority: Mrs. S. Rotanzi.] 



1911-12 

1912-13 

1913-14 

1914-15 

4-year means . 



a0.37 


0.00 


«0.70 


a0.45 


o0.20 


2.15 


1.17 


0.02 


9.96 


4.28 


2.50 


0.55 


22.35 


o .10 


.50 


.00 


2.55 


1.45 


.05 


2.57 


4.71 


2.51 


.83 


.50 


.50 


16-27 


.25 


.72 


.00 


1.50 


3.27 


2.09 


7.18 


4.55 


1.33 


2.78 


.46 


.80 


24.93 


.00 


.00 


.00 


1.27 


1.05 


3.08 


7.57 


8.01 


1.55 


5.32 


al.73 


.00 


29.58 


.18 


.31 


.18 


1.44 


1.49 


1.84 


4.62 


4.32 


3.84 


3.30 


1.30 


.46 


23.26 



a Estimated. 



DETAILED PRECIPITATION RECORDS. 



293 



Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

Mesa Grande (U. S. W. B.) (14); elevation, 3,450 feet. 

[Authorities: 1905 to Jan., 1909, Ed. H. Davis; 1909 to 1914-15, U. S. Weather Bureau. Three-inch South- 
ern Pacific Co. gage used, 1905 to Oct., 1908; subsequently U. S. Weather Bureau standard gage.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1905-6.. 


























47.03 


1906-7 


1 






















33.66 


1907-8 
























27.67 


1908-9 















15.65 
6.30 
8.99 
1.14 
4.07 
10.86 
10.85 

8.26 


8.84 
1.32 
7.30 
.00 
8.70 
7.13 
10.79 

6.29 


4.34 
3.92 
3.49 
15.31 
3.28 
1.96 
2.83 

5.02 


0.69 
.73 
2.92 
4.60 
1.90 
3.07 
5.59 

2.79 


0.14 
.07 
.20 

2.13 
.60 
.18 

6.34 

1.38 


0.00 
.00 
.00 
.29 
.75 
.78 
.00 

.26 


36.67 


1909-10 

1910-11 

1911-12 

1912-13 

1913-14 

1914-15 

6-year means 


Tr. 
0.10 
.37 
.21 
.23 
.05 

.17 


1.73 
.00 
.00 
.43 
.68 
.00 

.47 


Tr. 

0.42 
.73 
.09 
.48 
.07 

.30 


0.00 
1.46 

.47 
3.58 

.26 
1.51 

1.21 


5.48 
2.19 
.39 
1.82 
4.28 
1.23 

2.56 


10.00 

.68 

2.17 

.18 

1.86 

5.20 

3.35 


29.55 
27.75 
27.60 
25.64 
31.77 
44.46 

33.18 



Mesa Grande (Angels) (15); elevation, 3,450 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1911-12 

1912-13 

1913-14 

1914-15 

4-year means . . . 



a0.40 


0.00 


o0.80 


o0.50 


o0.40 


o2.30 


1.30 


0.07 


15.88 


5.30 


2.03 


a0.30 


.30 


.91 


a .00 


3.33 


1.56 


.00 


9.81 


8.57 


3.65 


1.57 


.78 


.67 


.26 


1.10 


.00 


.00 


5.45 


2.89 


12.47 


7.50 


2.70 


3.48 


.16 


.88 


.00 


.00 


.00 


1.64 


1.50 


4.98 


9.44 


11.88 


a3.50 


3.68 


o6.50 


a .05 


.24 


.50 


.20 


1.37 


2.23 


2.54 


8.25 


7.01 


6.43 


3.51 


2.37 


.48 



29.28 
31.15 
36.89 
43.17 

35.12 



Nellie (16); elevation, 5,350 feet. 

[Authorities: 1901 to Jan., 1909, T. O. Bailey; 1909 to 1914-15, U. S. Weather Bureau. Interpolations by 
using seasonal ratios from 5 nearby stations.] 



1901-2 

1902-3 


aO.OO 
.06 
.00 
Tr. 
.00 
.41 


oO.OO 
.00 
.00 
.90 
Tr. 
1.39 


a0.76 
.22 

a .30 
Tr. 
.44 
.66 


2.55 

.85 
.78 
1.18 
.27 
.25 


1.75 
5.32 
.01 
Tr. 
9.99 
4.57 


0.55 
5.26 
.00 
3.10 
2.68 
10.91 


17.60 


7.34 


10.21 


2.20 


0.25 


0.00 


o43.21 


1903-4 

1904-5 

1905-6 


1.42 
11.46 
7.62 


6.77 
15.09 
8.70 


12.37 
14.48 
36.88 


2.50 
2.43 
3.86 


.71 

6.07 
6.65 


.00 
.00 
.31 


o24. 86 
54.71 
77.40 


1906-7 




1907-8 
















1908-9 


a .10 
.11 
Tr. 
.47 
Tr. 
.45 
3.75 

.44 


o3.10 
1.70 
Tr. 
.00 
.05 
.87 

oO.OO 

.60 


a2.20 
.17 
.44 
.76 
.00 
.15 

aO.OO 

.47 


ol.40 

.00 

2.20 

.75 

3.30 

a .05 

2.24 

1.34 


al.60 

7.78 

3.64 

.60 

2.90 

a3.20 
1.53 

3.00 


a2.70 
17.34 
1.25 
3.65 
.00 
o3.30 
6.72 

3.75 


23.10 
7.76 

10.80 
1.45 
4.45 

17.68 

13.89 

10.66 


11.27 
1.40 
13.93 
.00 
14.20 
12.95 
16.78 

9.86 


6.51 
6.87 
10.25 
21.35 
9.45 
3.61 
5.08 

12.47 


.19 
1.08 
2.20 
7.90 
1.95 
4.56 
9.94 

3.53 


.14 

.00 

.25 

1.95 

1.20 

.47 

7.21 

2.26 


.00 
.00 
Tr. 
.18 
1.09 
1.44 
.05 

.28 


o52.31 


1909-10 


44.21 


1910-11 

1911-12 

1912-13 

1913-14 


44.96 
39.06 
38.59 

48.73 


1914-15 


o67. 19 


11-year means 


48.66 



Mendenhall Valley (17) ; elevation, 4,500 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1911-12 

1912-13 

1913-14 

1914-15 


a0.30 
.70 
.27 
.25 


0.00 
.83 
.75 
.00 


a0.40 
.00 
.30 
.00 


0.54 

2.17 

.00 

1.28 


oO.OO 

.98 

5.66 

1.41 


2.26 

.47 

3.10 

6.44 


0.39 
3.95 
12.37 
13.42 


0.10 
11.01 
9.17 
6.50 


19.18 
2.10 
3.10 
1.08 


5.41 
1.01 
1.98 
9.04 


1.50 
.50 
.20 

2.43 


a0.30 
.33 
.50 
.15 


30.38 
24.05 
37.40 
42.00 


4-year means 


.38 


.39 


.18 


1.00 


2.01 


3.07 


7.53 


6.69 


6.36 


4.36 


1.16 


.32 


33.46 



Oak Grove (18); elevation, 2,750 feet. 

[Authority: U. S. Weather Bureau.] 



1911-12 

1912-13 

1913-14 


0.44 
.33 


0.00 
.29 


0.94 
.00 


0.49 
.99 


0.02 
.49 


1.17 
a .00 


0.18 
2.41 
7.29 
8.13 

1.29 


0.08 
4.39 
6.02 
6.70 

2.24 


9.53 

ol.06 

1.69 

2.32 

5.29 


3.76 
.19 

1.28 
2.28 

1.98 


1.20 
.10 


0.24 
.10 


18.05 
10.35 


1914-15 












3.24 
.59 


2.12 
.65 


.00 
.17 




2-year means 


.39 


.15 


.47 


.74 


.25 


14.20 



a Estimated. 



294 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

Chihuahua Mountain (19)a; elevation, 4,200 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1911-12 

1912-13 

1913-14 

1914-15 

4-year means 


60.60 

.00 

1.08 

.00 

.42 


0.00 

.65 

3.15 

.00 

.95 


60.30 
.00 
.00 
.00 

.08 


0.15 

2.62 

.05 

61.90 

1.18 


0.00 

.87 

2.68 

63.00 

1.64 


0.73 

.00 
1.39 

4.82 

1.74 


0.04 
2.25 
6.75 
9.36 

4.60 


0.00 
5.01 
6.75 
5.28 

4.26 


10.15 
1.30 
1.52 
2.08 

3.76 


2.52 

.32 

2.35 

4.00 

2.29 


1.25 

.30 

.30 

62.20 

1.01 


0.35 
.21 
.00 
.03 

.15 


16.09 
13.53 
26.02 
632.67 

22.08 



Eagles Nest (20); elevation, 4,500 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1911-12 

1912-13 

1913-14 

1914-15... 



4-year means . 



60.14 


0.00 


60.50 


60.20 


0.09 


1.22 


24 


0.00 


5.14 


2.54 


0.81 


0.00 


.51 


.28 


.00 


3.99 


61.10 


.00 


1.36 


3.34 


.33 


.15 


.09 


.17 


.41 


2.82 


.00 


.00 


1.12 


1.09 


4.45 


3.19 


1.79 


2.26 


.00 


.04 


.16 


.00 


Tr. 


1.35 


1.56 


5.85 


9.28 


6.80 


.60 


4.02 


2.72 


.03 


.31 


.78 


.13 


1.38 


.97 


2.04 


3.83 


3.33 


1.97 


2.24 


.91 


.06 



Warner Springs (21); elevation, 3,165 feet. 

[Authority, U. S. Weather Bureau.] 



1900-1901 

1906-7 

1907-8 

1908-9 

1909-10 

1910-11 

1911-12 

1912-13 

1913-14 

1914-15 

9-year means. 



1.12 
.00 
.16 
L.26 
1.61 
.14 
.66 
.44 
.16 

.62 



1.72 
1.13 
2.11 
3.25 

Tr. 

.00 

.39 
2.10 

.00 

1.20 



0.21 
.00 
.81 

1.41 
.73 
.54 
.00 
.05 
.01 

.42 



0.23 
3.73 
.80 
.00 
.79 
.25 
3.07 
.18 



1.06 



1.93 
2.46 
.05 
.49 
2.66 
1.77 



1.52 
1.22 



1.25 



5.09 
1.08 

.76 
7.93 

.49 
1.10 

.00 

.98 
4.03 

2.38 



2.58 
6.13 
3.95 
5.78 
2.90 
4.61 
.16 
2.37 
6.07 
7.24 



5.98 
1.48 
3.61 
4.31 

.25 
4.71 

Tr. 
4.80 
4.23 
4.89 

3.14 



0.35 
4.40 
1.37 
2.38 
2.67 
2.36 
7.29 
1.04 
1.11 
2.45 

2.78 



0.20 
.25 
.60 
.08 
.12 
.38 

3.19 
.29 

1.49 

3.80 

1.13 



,52 



0.00 
.00 
.00 
.00 
.02 
.22 
.13 
.21 
Tr. 

.06 



Warner ranch house (22) ; elevation, 2,894 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1911-12 

1912-13 

1913-14 

1914-15 


60.50 

6 .50 

.51 

.51 

.51 


0.00 
.62 

2.30 
.00 

.73 


60.35 
.00 
.00 
Tr. 

.09 


0.18 

1.85 

.00 

.63 

.67 


0.00 

.82 

1.54 

1.30 

.92 


0.83 
.00 
.85 

2.89 

1:14 


0.35 
2.60 
7.64 
8.02 

4.65 


0.00 
3.89 
4.73 
5.54 

3.54 


7.52 

.37 

1.15 

2.09 

2.53 


2.99 

.75 

1.50 

4.04 

2.32 


1.29 
.13 
.00 

4.76 

1.55 


Tr. 
.11 

b .14 
.00 

.06 


14.01 

11.64 

620.36 

29.78 


4-year means 


18.95 



San Felipe (23) ; elevation, 3,600 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1911-12 

1912-13 

1913-14 

1914-15 

4-year means . . . 



60.50 


0.00 


60.40 


0.10 


0.05 


1.85 


0.30 


0.00 


14.50 


2.32 


1.55 


0.25 


.80 


.35 


.00 


2.80 


.33 


.05 


2.34 


6.00 


1.80 


.65 


.24 


.20 


.50 


1.75 


.00 


.25 


2.33 


1.32 


8.05 


7.80 


1.90 


2.30 


.00 


.22 


.50 


.00 


.11 


.40 


1.30 


2.14 


9.15 


8.40 


3.20 


4.75 


2.26 


.00 


.58 


.53 


.13 


.89 


1.00 


1.34 


4.96 


5.55 


5.35 


2.50 


1.01 


.17 



a Abandoned. 



6 Estimated. 



DETAILED PRECIPITATION RECORDS. 



295 



Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued. 

Matagual (24) ; elevation, 3,200 feet. 

[Authority, Volcan Land & Water Co. ,W .S. Post engineer.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1911-12 

1912-13 

1913-14 


o0.50 
.30 

. .27 
.00 

.27 


0.00 
.44 

1.95 
.00 

.60 


0.40 
.00 
Tr. 
Tr. 

.10 


0.29 

2.80 

.10 

.69 

.97 


0.03 

.89 

2.56 

1.24 

1.18 


1.24 

.25 
.95 

5.08 

1.88 


0.21 
3.24 
8.14 
9.52 

5.28 


Tr. 
6.16 
6.17 
9.76 

5.52 


11.19 

1.58 
1.50 

.82 

3.77 


3.56 

.63 

2.48 

6.16 

3.21 


1.50 

a. 56 

.00 

1.86 

.97 


0.33 
.14 
.62 
.00 

.27 


19.2 

16.95 

24.73 


1914-15 


35.14 


4-year means 


24.01 






Volcan Mountain (25) ; elevation, 4,800 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1911-12 


a0.50 
.50 
.98 
.00 

.49 


0.00 

1.06 

1.75 

.00 

.70 


a0.60 
.20 
.00 
.10 

.22 


o0.40 

4.54 

.11 

1.72 

1.69 


a0.38 
2.01 
4.60 
1.70 

2.65 


2.05 

.89 

3.33 

7.21 

3.37 


1.45 
4.80 
9.19 
8.67 

6.03 


0.00 
12.35 
7.31 
9.40 

7.27 


17.18 
3.80 
1.54 
6.23 

7.19 


7.65 
1.25 
2.43 
7.10 

4.61 


2.30 

.78 

.60 

4.68 

2.08 


a0.50 
.71 
.93 
.09 

.56 


32.93 


1912-13 


32.83 


1913-14 

1914-15 


32.77 
46.90 


4-year means 


36.36 



Pine Mountain (26) ; elevation, 2,500 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1911-12 


a0.75 


0.00 L.46 


a0.32 


a0.ll 


1.41 


0.61 Tr. 


11.86 


2.95 


1.24 


aO.lG 


19.81 


1912-13& 




1913-14 5 












i 












1914-15 b 


i 








i 















1 1 "' 











Aguanga (27) ; elevation, 1,988 feet. 

[Authority, U. S. Weather Bureau.] 



1908-9 




1.05 


0.51 


0.14 


0.07 


0.50 


4.44 


3.28 


1.95 


0.00 


0.00 


0.00 


11.94 


1909-10 


0.15 


1.61 


.43 


.00 


1.90 


4.16 


4.49 


.72 


1.82 


.14 


.00 


.00 


15.42 


1910-11 


.19 


.00 


.13 


.68 


1.53 


.16 


4.76 


3.89 


1.42 


.57 


.00 


.00 


13.33 


1911-12 


.14 


.00 


.54 


.25 


.00 


.63 


.34 


.00 


6.92 


2.94 


1.05 


.02 


12.83 


1912-13 


.32 


.44 


.00 


1.37 


.49 


.00 


1.61 


3.10 


.65 


.16 


.00 


.05 


8.19 


1913-14 


.16 


1.07 


.82 


.16 


1.26 


.23 


5.68 


3.97 


.82 


.96 


.12 


.18 


15.43 


1914-15 


.00 


.00 


.22 


.58 


.99 


2.27 


5.37 


5.91 


1.57 


2.20 


1.58 


.00 


20.69 


7-year means 


.14 


.60 


.38 


.45 


.89 


1.13 


3.82 


2.98 


2.16 


1.00 


.39 


.04 


13.98 



Julian (28) ; elevation, 4,200 feet. 

[Authority, U. S. Weather Bureau.] 



1879-80... 
1880-81... 
1881-82... 
1882-83... 
1883-84... 
1890-91... 
1891-92... 
1892-93... 
1893-94... 
1894-95... 
1895-96... 
1896-97... 
1897-98... 



1899-1900. 
1900-1901. 
1901-2... 
1902-3... 
1903-4.... 
1904-5... 



0.00 
.00 
.00 
.00 
.00 



.00 
.00 

2.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 

2.00 
.00 

1.50 



0.00 
.00 
.00 
.00 
.00 



0.00 
.00 
.00 
.00 
.00 



.10 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
1.00 
.00 
.00 
.00 
.00 



0.00 
.00 
.00 
.00 

2.75 



.00 
1.00 
1.70 

.00 

.00 
2.00 
2.00 

.00 
2.50 

.00 
1.00 
1.00 

.50 

.50 



2.13 
2.25 
1.88 
5.13 
.00 



.00 

1.00 

7,00 

.00 

2.00 

.00 

.00 

.00 

1.50 

6.00 

1.00 

3.00 

.00 

.00 



4.50 
2.75 



5.25 
5.00 



.00 
1.60 

.00 
9.50 
2.50 

.00 

.00 
3.00 
1.00 

.00 

.10 
3.25 

.00 
2.25 



1.50 

5.13 

5.13 

10.04 

2.25 

4.70 

3.70 

4.40 

15.00 

15.50 

1.00 

3.50 

.00 

.00 

4.00 

7.00 

6.00 

2.50 

.50 

6.75 



5.75 
4.88 
3.38 
6.63 

20.63 
3.00 
2.40 
3.20 

12.50 

3.30 

.00 

4.20 

2.00 

.00 

.00 

8.00 

5.75 

8.00 

2.00 

11.50 



9.25 
8.13 
7.13 
9.13 

15.63 

12.00 
7.00 

13.00 
2.00 
2.00 
3.00 
5.60 
2.00 
5.75 
1.00 
.75 
8.00 

10.50 
2.25 

12.25 



7.50 
2.75 
4.88 
4.13 
10.63 
6.80 
3.10 

.00 

.00 
1.25 
3.50 
6.00 
2.50 

.00 
6.75 

.00 
2.60 

.00 
8.25 
1.25 



0.00 

.00 

.00 

.00 

3.63 

2.50 

5.50 

.90 

.50 

.50 

.00 

1.10 

5.00 

2.00 

3.50 

2.00 

.00 

.50 

1.75 

4.70 



0.00 
.00 
.00 
.00 
.00 
.00 
.45 
.00 
.20 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 



a Estimated. 



& Abandoned. 



296 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

Julian (28) ; elevation, 4,200 feet— Continued. 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1905-6 

1906-7 

1907-8 

1908-9 

1909-10 

1910-11 

1911-12 


.00 

.00 

.00 

2.60 

1.45 

2.35 

.50 

.85 

.58 

.21 

.48 


.00 
.00 
.00 
.50 

1.40 
.00 
.00 
.45 

2.40 
.05 

.18 


.25 

.00 
.00 
1.15 
.00 
.00 
.30 
.00 
.00 

.11 

.10 


.00 

.00 
2.50 
1.10 

.00 
1.50 

.60 
3.41 

.65 
1.05 

.89 


11.50 
3.00 
1.00 
1.00 
4.30 
2.55 
.40 
2.11 
4.08 
1.22 

2.21 


.00 
8.00 

.50 
1.50 
6.05 

.65 
2.15 

.40 
3.06 
7.70 

2.74 


5.00 
9.00 
5.75 

8.90 
7.10 
8.35 
1.60 
3.88 
11.04 
13.25 

5.77 


4.50 
4.25 
8.25 
7.00 

.70 
8.25 

.00 
3.73 
6.96 
12.78 

5.54 


17.00 
6.00 
3.25 
4.05 
2.15 
4.00 

15.90 
3.56 
2.01 
3.42 

6.40 


5.00 

1.00 

2.75 

.00 

• 7Q 

.70 

3.10 

1.26 

3.96 

4.83 

3.05 


2.00 
.75 
.50 
.00 
.00 
.00 

1.95 
.62 
.35 

7.76 

1.57 


.25 
.50 
.00 
.00 
.00 
.00 
.20 
.55 
.42 
Tr. 

.09 


45.50 
32.50 
24.50 
27.80 
23.85 
28.35 
26.70 
20.82 
35.51 
52.38 

29.02 


1912-13 


1913-14 


1914-15 


29-year means 








Cuyan 

[Autl 


laca (2 

lority, 


9) ; elevation, 4,677 feet. 

IT. S. Weather Bureau.] 













1888-89.. 

1889-90.. 

1890-91.. 

1891-92.. 

1892-93.. 

1893-94.. 

1894-95.. 

1895-96.. 

1896-97. 

1897-98.. 

1898-99. 

1899-1900. 

1900-1901 

1901-2... 

1902-3... 

1903-4... 

1904-5.. 

1905-6.. 

1906-7... 

1907-8... 

1908-9. 

1909-10.. 

1910-11.. 

1911-12.. 

1912-13.. 

1913-14.. 

1914-15. 





0.93 


0.04 


a0.09 


3.82 


8.33 


13.30 


o3.34 


a4.62 


12.85 


3.44 


2.22 


0.00 






.00 


1.71 


.03 


o4.27 


a2.94 


o20.73 


al3.56 


o21.16 


a5.58 


1.02 


3.92 


.00 






.09 


.90 


1.45 


.58 


3.62 


12.14 


.00 


34.70 


1.87 


3.50 


3.69 


.00 






.04 


.30 


.69 


.00 


.45 


6.75 


7.23 


6.47 


7.76 


3.35 


5.90 


.67 






.00 


.00 


.00 


.30 


2.87 


3.76 


5.55 


9.13 


o20.40 


1.00 


1.00 


.00 






1.20 


.30 


.00 


1.90 


3.30 


3.75 


o4.36 


o3. 36 


2.90 


.00 


1.00 


.50 






.00 


.50 


.30 


.00 


.00 


12.80 


a30.98 


4.60 


5.89 


1.10 


1.16 


.00 






.00 


.00 


.03 


1.03 


6.01 


1.66 


5.77 


.20 


7.91 


1.78 


.92 


.00 






1.29 


.87 


1.06 


4.73 


3.45 


3.74 


6.32 


O10.27 


a9.56 


.22 


.38 


.00 






.00 


.00 


.36 


5.09 


1.07 


a3.36 


o7.77 


1.97 


o5.04 


1.24 


5.97 


.00 






.00 


1.32 


.00 


.00 


.88 


a2.56 


o7.13 


a2. 73 


7.23 


.98 


.47 


2.96 







.04 


Tr. 


.00 


4.51 


a4.54 


2.49 


3.62 


.26 


2.51 


6.69 


4.03 


.10 






.28 


.00 


.92 


.74 


11.97 


.04 


8.17 


13.26 


2.32 


1.24 


3.87 


.00 






Tr. 


.09 


.08 


1.94 


1.48 


.52 


8.17 


7.50 


13.82 


2.09 


.14 


.17 






1.54 


.00 


Tr. 


1.01 


5.09 


3.66 


3.96 


06. 30 


6.13 


8.21 


.69 


.00 






.00 


.28 


1.28 


.53 


.04 


.16 


.78 


3.76 


12.75 


2.64 


1.15 


.00 






.20 


1.25 


.15 


1.18 


.00 


2.95 


9.87 


15.91 


15.63 


3.64 


7.11 


.00 






.00 


Tr. 


1.01 


Tr. 


10.15 


2.78 


5.44 


7.40 


22.41 


3.54 


3.37 


.14 






.10 


3.00 


.90 


.80 


3.68 


9.13 


9.48 


3.22 


11.38 


1.71 


.64 


.87 






.00 


.00 


.00 


3.40 


1.31 


1.80 


6.67 


9.30 


3.25 


2.77 


1.85 


.00 






Tr. 


2.87 


1.82 


2.30 


1.24 


.70 


15.16 


12.50 


8.85 


.21 


.00 


.00 






.16 


1.30 


.30 


.06 


6.07 


11.76 


6.33 


1.35 


5.19 


.92 


.00 


.00 






1.50 


.09 


.33 


1.86 


2.62 


1.12 


10.19 


8.26 


4.39 


1.79 


Tr. 


.00 






.64 


Tr. 


.29 


.68 


.26 


2.35 


1.30 


.02 


19.87 


4.38 


1,69 


.42 






.84 


.64 


.01 


5.53 


2.40 


.07 


5.38 


11.88 


2.12 


.93 


.51 


.71 






.52 


2.38 


.02 


.34 


4.86 


3.33 


9.75 


6.94 


2.35 


3.80 


.04 


.49 






.04 


1.33 


.20 


1.63 


1.18 


8.31 


11.48 


12.32 


3.67 


7.41 


8.22 


.00 


leans . . 




.35 


.71 


.42 


1.79 


3.33 


5.03 


7.69 


8.13 


8.28 


2.58 


2.22 


.26 



52.98 
74.92 
62.54 
39.61 
44.01 
22.57 
57.33 
25.31 
41.89 
31.87 
26.26 
28.79 
42.81 
36.00 
36.59 
23.37 
57.89 
56.24 
44.91 
30.35 
45.65 
33.44 
32.15 
31.90 
31.02 
34.82 
55.79 

40.78 



[Authorities: 1875 to 1886- 



Escondido (30); elevation, 657 feet. 

Maj.Merriam; 1887 to 1896-97, Escondido Land & Town Co.; 1897 to 1914-15, 
U. S. Weather Bureau.] 



1875-76 


0.00 


0.00 


2.50 


0.00 


3.51 


0.42 


6.04 


4.03 


3.12 


0.38 


0.81 


0.00 


20.81 


1876-77 


.00 


.00 


.00 


.05 


.16 


.07 


3.80 


2.87 


1.00 


.42 


.00 


.00 


8.37 


1877-78 


.00 


.00 


.03 


.09 


.78 


4.03 


3.95 


7.90 


2.49 


5.66 


1.40 


.47 


26.80 


1878-79 


.00 


.00 


.00 


.28 


.35 


.98 


3.26 


1.34 


.41 


1.59 


.18 


.33 


8.72 


1879-80 


.00 


.00 


.00 


.45 


3.50 


4.38 


1.50 


2.10 


2.65 


5.00 


.25 


.00 


19.83 


1880-81 


.00 


.10 


.00 


.75 


.75 


4.05 


.91 


.70 


2.75 


.66 


.00 


.00 


10.67 


1881-82 


.00 


.00 


.10 


1.20 


.25 


.60 


3.80 


2.87 


1.00 


.30 


.20 


.00 


10.32 


1882-83 


.00 


.00 


.08 


.68 


.84 


.20 


1.03 


1.40 


1.30 


.87 


1.30 


.00 


7.70 


1883-84 


.00 


.00 


.00 


1.45 


.00 


3.58 


2.22 


9.83 


8.68 


3.26 


2.00 


1.05 


32.07 


1884-85 


.00 


.00 


.00 


.30 


.48 


4.96 


.45 


.60 


.00 


2.61 


.00 


.00 


9.40 


1885-86 


.00 


.00 


.00 


.00 


4.68 


.75 


7.33 


.80 


4.71 


2.60 


.00 


.00 


20.87 


1886-87 


.00 


.00 


.00 


.20 


2.72 


.20 


.12 


4.73 


.00 


1.85 


.70 


.00 


10.52 


1887-88 


.00 


.00 


.00 


.25 


2.45 


3.60 


3.45 


1.90 


3.70 


.50 


.00 


.00 


15.85 


1888-89 


.00 


.00 


.00 


.62 


3.08 


5.70 


1.75 


1.07 


5.75 


.50 


.00 


.00 


18.47 


1889-90 


.00 


.00 


1.00 


3.25 


1.25 


4.55 


3.98 


4.11 


1.75 


.50 


.50 


.00 


20.89 


1890-91 


.00 


.00 


.00 


.75 


.50 


3.00 


.10 


8.57 


.78 


1.25 


.00 


.00 


14.95 


1891-92 


.00 


.00 


.00 


.00 


.50 


1.25 


1.75 


2.50 


3.03 


.40 


2.17 


.00 


11.60 


1892-93 


.00 


.00 


.00 


.01 


2.60 


1.50 


2.20 


3.00 


8.63 


.42 


.00 


.00 


18.36 


1893-94 


.00 


.00 


.00 


.65 


.65 


2.55 


.80 


.50 


.75 


.00 


.00 


'.00 


5.90 



a Record as published by U.S. Weather Bureau does not include snow; latter has been added from rec- 
ords of Cuyamaca Water Co., by W. S. Post, engineer. 



DETAILED PRECIPITATION RECORDS. 



297 



Table 64. — Monthly and annual precipitation^ at 106 stations in or near San Diego 

County — Continued . 

Escondido (30) ; elevation, 657 feet— Continued. 



July. Aug. Sept. Oct. Nov. Dec. Jan. Feb. Mar. Apr. May. June. Total. 



1894-95... 



1896-97... 
1897-98... 



1899-1900. 
1900-1901 . 
1901-2... 
1902-3... 
1903-4... 
1904-5... 
1905-6... 
1906-7... 
1907-8... 
1908-9... 
1909-10.. 
1910-11.. 
1911-12.. 
1912-13.. 
1913-14.. 
1914-15.. 



.00 
.00 
.00 
.00 
.00 
.00 
Tr. 
Tr. 
.15 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.25 
.11 
.00 
.07 
.00 



.00 
.00 
.00 
Tr. 
.00 
Tr. 
.00 
.04 
.00 
.00 
.00 
.00 
.03 
.00 
1.00 
.22 
Tr. 
.00 
.37 
.00 
.00 



40-year means . 



01 .04 



.00 
.00 
.00 
Tr. 
.01 
.00 
.03 
00 
.00 
.32 
a. 02 
.00 
.19 
.00 
.46 
.05 
.00 
.02 
.14 
.07 
Tr. 

.13 



.10 
.25 

2.30 

1.52 
.00 
.61 
.30 
.62 
.28 
.12 
.53 
.13 
.07 

1.98 
.45 
.00 

1.08 
.05 
.56 
Tr. 
.92 



.00 

1.42 

1.05 

.05 

.11 

1.99 

4.05 

.43 

2.35 

.03 

.00 

4.45 

1.34 

.14 

.73 

3.93 

1.27 

.10 

.79 

2.54 

1.41 



4.51 
.25 

1.85 
.75 

1.48 

1.62 
.00 
.05 

3.04 
.05 

1.68 
.82 

5.51 
.98 

1.07 

7.71 
.20 
.94 
.02 

1.11 

2.95 



10.26 
2.42 
3.95 
2.48 
3.23 
5.18 
2.86 
2.59 
1.58 

.41 
3.97 
2.78 
4.96 
5.07 
7.23 
4.03 
4.96 

.67 
1.79 
6.53 
7.06 



1.25 

.00 
4.75 

.68 
1.13 

.20 
5.21 
3.54 
3.67 
2.66 
9.29 
2.14 
1.60 
3.31 
4.38 

.49 
4.26 

.00 
4.21 
5.62 
5.41 



1.35 

3.48 
1.60 
1.53 
2.11 
.79 
.52 
3.68 
2.78 
3.79 
5.75 
11.98 
3.48 
1.05 
2.76 
1.82 
2.04 
8.04 
1.46 
1.57 
1.55 



.75 
.10 
.00 

.48 
.29 

2.23 
.18 
.67 

3.84 
.47 
.45 

1.59 
.43 
.77 
.00 
.58 

1.38 

3.11 
.70 

1.22 

3.72 



57 1.43 2.07 3.31 3.12 2.89 1.29 



.35 
.00 
.00 

1.19 
.15 

1.27 

1.31 
.00 
Tr. 
.30 

1.80 

1.46 
.09 
.22 
.13 
.00 
Tr. 

1.58 
.17 
.24 

2.35 

.55 



.00 
.00 
.00 
.00 
.96 
Tr. 
.00 
.04 
.00 
.00 
.00 
.08 
.19 
.00 
.00 
.00 
.00 
.08 
.10 
.14 
.00 



18.57 
7.92 
15.50 
8.68 
9.47 
13.89 
14.46 
11. 66 
17.69 
8.15 
23.49 
25.43 
17.89 
13.52 
18.21 
18.83 
15.44 
14.70 
10.31 
19.11 
25.37 

15.51 





Head of Escondido ditch (31); elevation, 1,986 feet 

[Authority, Escondido Mutual Water Co. 


' 








1896-97 








2.75 
1.60 


1.17 

1.85 

.26 


2.10 

1.25 

1.45 

64. 55 


7.35 
3.80 
1.35 
2.60 
3.70 


7.02 
.70 

1.80 
.03 

7.05 


4.50 
2.42 
2.92 
1.30 
1.55 


0.00 
.10 
.40 

2.72 
.25 


0.00 




24.89 


1897-98 








11.72 


1898-99 








.00 
1.92 


1.35 


9.53 


1899-1900 










13 12 


1900-1901 










4.97 


.00 


17.52 


1901-2 
















1902-3 










3.19 


3.40 


2.10 


3.60 


4.40 


5.15 


.00 




21.84 


1903-4 












1904-5 










1.25 

5.45 

2.75 

.91 

.80 

4.85 

1.63 

.25 






1.80 
3.93 
1.70 
5.45 
4.25 
.45 
6.97 

"6" 75" 
10.20 
10.40 

4.42 


9.55 
21.15 
6.00 
2.30 
4.22 
5.15 
4.48 
12.80 
.55 
2.70 
2.52 

3.85 


1.40 


4.25 






1905-6 










"3. '65' 
1.50 
1.48 
8.83 
.33 
2.00 


2.30 
7.00 
6.65 

.11.10 

4.05 

5.02 

.60 

2.90 

10.70 
8.85 

5.18 






1906-7 








.10 

5.46 
.55 


1.15 

1.25 

.13 

.50 
1.43 

3.80 
1.02' 
2.45 
5.28 

1.71 


.35 
.75 
.17 




22.10 


1907-8 








24.27 


1908-9 




1.00 


0.35 


24.05 


1909-10 




23 83 


1910-11 








.70 
07 


.03 

2.25 

.55 

.28 

3.44 

.65 


"."ii* 

.40 

.05 

.15 


20 59 


1911-12 








21.77 


1912-13 


0.25 






12.43 


1913-14 










2.10 
6.76 

2.59 


28.83 


1914-15 












37.30 


15-year means 


.02 


.07 


.02 


.75 


1.51 


20.92 


[Authority 


Hot Springs Mountain (32) ; elevation, 6,200 feet. 

Volcan Land & Water Co. and U. S. Forest Service, W. S. Post, engin 


eer.] 




1912-13 

1913-14 


a0.51 

2.00 

.03 

.85 


a0.28 

3.06 

.10 

1.15 


0.00 
.20 
.65 

.28 


a4.00 
.08 
.95 

1.68 


al.10 
3.46 
1.20 

1.92 


0.00 
1.08 
2.79 

1.29 


3.27 
3.55 
3.70 

3.51 


4.26 
3.70 
4.04 

4.00 


0.56 

.77 
.43 

.59 


a0.15 

.90 

4.08 

1.71 


a0.09 

.00 

2.21 

.77 


a0.17 
.00 
.00 

.06 


14.39 

18.80 


1914-15 

3-year means 


20.18 
17.79 



Elsinore (33); elevation, 1,234 feet. 

[Authority, U. S. Weather Bureau.] 



1886-87 














0.16 
6.09 
1.41 
a2.49 
2.29 
3.43 


7.01 
.80 


0.06 
5.87 


1.54 

.08 


0.02 
.09 


0.05 
.00 




1887-88 

1888-89 


Tr. 
0.10 


0.00 
.00 


0.16 
.06 


0.32 
.69 


1.72 
2.93 


4.04 
5.37 


19.17 


1896-97 


al.76 
.15 
.48 


o.77 
.82 
.96 


.00 
.23 
.00 


.03 
1.32 
Tr. 


.00 
.01 
.18 




1897-98 

1898-99 


.00 
.00 


.29 
.00 


.26 
.00 


1.06 
.00 


Tr. 
.04 


.19 
1.38 


6.62 
6.47 



a Estimated. 



b Total to date. 



298 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

Elsinore (33); elevation, 1,234 feet — Continued. 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1899-1900 


.00 

Tr. 
.00 
.08 

a. 02 
.00 
.00 
.00 

Tr. 
.00 
.00 
.09 
.00 

Tr. 


Tr. 

Tr. 

.74 

.00 

a. 05 

1.12 
.00 
.03 
.00 
.73 
.55 
.00 
.00 
.10 


Tr. 
Tr. 
.00 
.00 
.40 
.82 
Tr. 
.19 
.00 
.30 
.00 
Tr. 
.58 
.00 


.98 
.06 

1.08 
.13 
.05 

Tr. 
.12 
.07 

2.99 
.53 
.09 
.53 
.15 
.87 


.69 

5.04 

.35 

1.26 

.00 

.00 

5.61 

1.34 

.08 

.24 

1.43 

.19 

.20 

a. 40 


.55 
.00 
.00 

3.04 

Tr. 
.91 
.20 

5.51 
.41 
.82 

6.65 
.14 
.80 
.00 


1.56 

3.59 

2.30 

.81 

.19 

5.32 

2.78 

4.80 

4.93 

6.51 

3.74 

5.81 

.08 


.00 
4.61 
2.03 
2.50 
1.49 
7.72 
2.14 
2.24 
2.80 
3.57 

.14 
3.24 

.00 


.39 

.42 

2.64 

6.55 

4.14 

4.36 

11.98 

3.68 

.47 

2.29 

1.19 

1.38 

6.73 


.77 
.10 
.30 

1.71 
.28 
.30 

1.59 
.07 
.18 
.00 
.35 
.25 

1.80 


1.04 
.47 

Tr. 

Tr. 
.03 
.92 

1.46 
.04 
.04 
.00 
.00 
.00 
.13 


.00 
Tr. 
.21 
.00 
.00 
.00 
.08 
.05 
.00 
.04 
.00 
.00 
.00 


5.98 
14.29 
9.65 


1900-1901 

1901-2 


1902-3 

1903-4 

1904-5 


16.08 

6.65 

21.47 


1905-6 


25.96 


1906-7 


18.02 


1907-8 

1908-9 

1909-10 

1910-11 


11.90 
15.03 
14.14 
11.63 


1911-12 

1912-13 .. 


10.47 


1913-14o 
















16-year means 


.01 


.22 


.17 


.51 


1.18 


1.54 


3.39 


2.12 


3.37 


.50 


.35 


.04 


13.34 



Oceanside (34). 
[Authorities: 1892 to 1908-9, J. A. Tulip; 1908-9, H. D. Brodie; 1909to 1914-15, U. S. Weather Bureau.] 



1893-94 

1894-95 

1895-96 

1896-97 

1897-98 

1898-99 

1899-1900 

1900-1901 

1901-2 

1902-3 

1903-4 

1904-5 

1905-6 

1906-7 

1907-8 

1908-9 

1909-10 

1910-11 

1911-12 

1912-13 

1913-14 

1914-15 

23-year means. 



0.00 


0.00 


0.00 


0.27 


1.85 


3.07 


1.33 


1.92 


2.41 


2.25 


0.00 


0.00 


.00 


.00 


.58 


.55 


.85 


2.29 


1.14 


.00 


1.54 


.00 


.00 


.00 


.00 


.00 


.43 


.00 


.00 


3.98 


8.10 


.00 


.95 


.52 


.35 


.00 


.00 


.00 


.00 


.00 


1.85 


.00 


2.92 


.00 


2.35 


.00 


.00 


.00 


.00 


.00 


.00 


1.05 


1.14 


1.98 


4.70 


4.66 


2.55 


.00 


.00 


.00 


.00 


.00 


.00 


2.19 


.00 


.00 


2.84 


.37 


1.05 


.46 


.00 


.00 


.00 


.00 


.00 


.00 


.00 


.76 


2.75 


.30 


.90 


.07 


.21 


.00 


.00 


.00 


.00 


.74 


1.74 


1.65 


2.69 


.10 


.33 


1.07 


1.29 


.00 


.00 


.00 


.00 


.33 


2.16 


.00 


3.08 


3.43 


.20 


.00 


.00 


.00 


.00 


.00 


.00 


.29 


.84 


.18 


3.92 


.00 


3.00 


.53 


.00 


.00 


.14 


.00 


.00 


.27 


1.85 


3.97 


1.33 


1.92 


2.41 


2.25 


.00 


.00 


.00 


.00 


.00 


.00 


.00 


.15 


.19 


1.39 


2.45 


.19 


.15 


.00 


.00 


.00 


.00 


1.50 


.00 


1.72 


2.92 


6.16 


2.58 


.20 


1.21 


.00 


.00 


.00 


.00 


.00 


3.51 


.00 


2.60 


1.53 


6.62 


.73 


.46 


.00 


.00 


.00 


.00 


.00 


1.47 


3.27 


3.54 


.00 


2.78 


.27 


.00 


.00 


.00 


.00 


.00 


1.59 


.00 


1.13 


3.21 


2.17 


.69 


.62 


.00 


.00 


.00 


1.10 


.00 


.00 


.78 


.72 


3.41 


2.23 


2.28 


.00 


.05 


.00 


.00 


.00 


.00 


.00 


2.72 


4.78 


1.62 


.11 


1.76 


.07 


Tr. 


.06 


.28 


.01 


.05 


.66 


.77 


.37 


3.94 


3.59 


1.65 


.91 


.03 


Tr. 


.15 


Tr. 


.23 


.33 


.07 


.56 


.71 


.42 


5.78 


2.36 


.74 


.32 


.02 


.05 


Tr. 


.44 


.68 


Tr. 


1.44 


2.78 


.53 


.24 


.16 


.16 


.05 


Tr. 


Tr. 


.05 


2.00 


1.04 


5.55 


2.99 


1.27 


.66 


.25 


.29 


Tr. 


Tr. 


Tr. 


1.41 


1.29 


3.42 


6.51 


5.75 


.50 


2.73 


.51 


Tr. 


.03 


.05 


.06 


.51 


1.11 


1.52 


3.06 


1.81 


2.03 


.70 


.24 


.03 



13.10 
6.95 
14.33 
7.12 
16.08 
6.91 
4.99 
9.61 
9.20 
8.76 
14.14 
4.52 
16.29 
15.45 
11.33 
9.41 
10.57 
11.12 
12.26 
11.67 
6.50 
14.15 
22.12 

11.15 



Poway (35) ; elevation, 460 feet. 

[Authority, U. S. Weather Bureau.] 



1878-79 












1.57 

4.72 

3.56 

.73 

.27 

2.40 

5.91 

.90 

.20 

2.70 

1.37 

2.49 

3.06 

.57 

2.42 

.72 

1.87 

1.29 


2.88 
1.13 
1.16 
6.40 

.88 
1.59 

.72 
6.34 

.09 
4.01 
1.78 

.79 
12.65 
2.50 
4.30 
2.78 
2.98 
3.89 


1.50 

1.54 

.60 

2.69 

1.76 

9.40 

.35 

.77 

4.87 

.89 

2.42 

1.29 

1.08 

Tr. 

4.91 

.22 

.61 

.32 


0.00 
1.76 
2.86 
1.13 
1.87 
6.96 

.34 
3.24 

.34 
4.85 
8.26 
1.64 
1.24 
4.73 
2.89 
1.75 
1.16 

.69 


1.30 

3.10 

1.14 

.84 

1.36 

4.81 

2.05 

2.78 

2.01 

.10 

.51 

.14 

.46 

.96 

.00 

.33 

.05 

1.48 


0.08 
.09 
.03 
.04 

1.34 

2.26 
.63 
.00 
.34 
.51 
.00 
.21 
.26 
.31 
.12 

1.55 
.44 

1.48 


0.20 
.00 
.00 
.09 
.00 
.44 
.07 
.00 
.00 
.00 
Tr. 
.15 
.00 
.00 
.00 
.00 
.51 
.05 




1879-80 

1880-81 


0.00 
.06 
.00 
.00 
.00 
.00 
.00 
Tr. 
.00 


0.00 
.16 
.04 
.01 
Tr. 
Tr. 
Tr. 
.02 
Tr. 


0.00 
Tr. 
.03 
.04 
.00 
Tr. 
.00 
.00 
.63 


0.30 
.74 

1.17 
.29 

1.59 
.24 
.06 
.10 
.00 


2.75 
.30 
.20 
.60 
.00 
.38 
2.71 
1.50 
2.04 
1.45 
1.36 
.00 
1.44 
1.54 
.08 
.29 
1.29 


15.39 
10.61 


1881-82 

1882-83 

1883-84 


13.36 

8.42 

29.45 


1884-85 


10.69 


1885-86 


16.80 


1886-87 

1887-88 


9.47 
15.73 


1892-93 




1893-94 

1894-95 


.00 
.00 
.00 
Tr. 
.00 
.00 
.00 


.00 
.06 
Tr. 
.08 
.00 
Tr. 
.00 


.06 
Tr. 
.00 
.00 
.02 
.05 
.00 


.19 
Tr. 
.25 
1.51 
1.70 
.00 
.78 


8.32 
18.81 


1895-96 


10.76 


1896-97 

1897-98 

1898-99 


17.77 
9.15 
7.96 


1899-1900 


11.27 



a Estimated. 
b Abandoned. 

c Gage on bluff above ocean at 30 feet elevation 1892-1909, and half a mile back from ocean at 67 feet 
elevation 1910-1915. 



DETAILED PRECIPITATION RECORDS. 



299 



■Monthly and annual precipitation at 106 stations in or near San Diego 
County — Continued . 

Poway (35); elevation, 460 feet— Continued. 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1900-1901... 


.00 
Tr. 
.80 
.00 
Tr. 
.00 
Tr. 
.00 
.08 

.04 


.00 
.02 
.00 
Tr. 
Tr. 
.00 
Tr. 
.00 
.47 

.03 


Tr. 
Tr. 
.00 
.17 
Tr. 
.32 
.36 
Tr. 
.30 

.08 


.25 
.24 

.38 
.14 
.19 
.17 
.03 
1.66 
.48 

.50 


3.19 
.46 

3.03 
.02 
.00 

4.43 

1.16 
.48 

1.23 

1.22 


.00 
.22 

2.27 
.06 

1.85 
.84 

6.34 
.76 
.85 

1.88 


2.28 
2.47 
2.22 
.47 
4.25 
2.25 
4.67 
3.95 
7.49 

3.29 


5.82 
2.64 
2.83 
2.95 
7.99 
2.88 
1.13 
3.56 
4.48 

2.62 


.34 
3.13 
2.96 
3.74 
3.24 
8.55 
2.45 
1.09 
2.64 

2.62 


.61 

.59 
1.95 
.41 
.42 
1.06 
.30 
.75 
Tr. 

1.11 


.65 
.10 
.11 
.28 
1.90 
1.27 
.09 
.44 
Tr. 

.57 


.01 
.01 
.00 
.00 
.00 
Tr. 
.20 
.00 
.00 

.06 


13.15 


1901-2 

1902-3 

1903-4 


9.88 
16.55 

8.24 


1904-5 

1905-6 

1906-7 

1907-8 


19.84 
21.77 
16.73 
12.69 


1908-9 

25-year means 


18.02 
14.01 



Sweetwater dam (36); elevation, 310 feet. 

[Authority, Sweetwater Water Co., J. F. Covert, engineer.] 



1888-89 


0.00 


0.00 


0.48 


0.36 


2.81 


3.22 


1.56 


1.85 


2.84 


0.36 


0.21 


0.33 


14.02 


1889-90 


.01 


.09 


.00 


2.60 


.10 


8.05 


2.26 


2.73 


.74 


.13 


.41 


.00 


17.12 


1890-91 


.00 


.07 


.87 


.00 


.93 


2.43 


.62 


5.29 


.23 


1.27 


.83 


.09 


12.63 


1891-92 


.00 


.03 


.04 


.02 


.13 


1.75 


1.57 


3.47 


1.20 


.28 


1.46 


.00 


9.95 


1892-93 


.00 


.02 


.00 


.15 


.68 


1.48 


1.01 


1.17 


6.50 


.27 


.20 


.00 


11.48 


1893-94 


.16 


.00 


.00 


.33 


.84 


2.08 


.36 


.71 


1.69 


.04 


.15 


.00 


6.36 


1894-95 


.00 


.00 


.00 


.04 


.00 


3.03 


10.06 


1.09 


1.18 


.79 


.00 


.00 


16.19 


1895-96 


.00 


.00 


.02 


.45 


1.45 


.43 


1.70 


.00 


2.52 


.65 


.05 


.00 


7.27 


1896-97 


.05 


.11 


.04 


.69 


1.14 


1.69 


3.11 


2.95 


2.27 


.00 


.02 


.00 


12.07 


1897-98 


.00 


.00 


.00 


1.50 


.06 


.45 


2.23 


.13 


1.50 


.39 


.79 


.00 


7.05 


1898-99 


.00 


.00 


.00 


.00 


.07 


.76 


2.40 


.70 


.89 


.23 


.11 


.58 


5.74 


1899-1900 


.00 


.00 


.00 


.41 


1.66 


.77 


.57 


.00 


.37 


1.06 


1.66 


.00 


6.50 


1900-1901 


.00 


.00 


.00 


.25 


1.63 


.00 


1.75 


4.22 


.54 


.11 


.74 


.00 


9.24 


1901-2.. 


.00 


.00 


.03 


.43 


.19 


.00 


1.96 


1.60 


2.39 


.49 


.00 


.00 


7.09 


1902-3 


.90 


.00 


.00 


.11 


1.29 


2.80 


.77 


2.41 


1.28 


.89 


.00 


.00 


10.45 


1903-4 


.00 


.00 


.00 


.25 


.00 


.12 


.11 


1.85 


2.30 


.14 


.34 


.00 


5.11 


1904-5 


.00 


.00 


.00 


.34 


.00 


2.15 


2.02 


6.02 


3.47 


.35 


1.05 


.00 


15.40 


1905-6 


.19 


.00 


.50 


.24 


3.69 


.43 


.99 


2.66 


5.46 


1.67 


.85 


.00 


16.68 


1906-7 


.00 


.00 


.25 


.03 


1.20 


4.37 


3.67 


.56 


2.35 


.18 


.08 


.39 


13.08 


1907-8 


.00 


.00 


.00 


1.85 


.08 


.31 


3.10 


3.21 


1.06 


.65 


.25 


.00 


10.51 


1908-9 


.00 


.67 


.56 


.48 


.82 


.70 


4.06 


2.07 


2.73 


.00 


.00 


.00 


12.09 


1909-10 


.01 


.00 


.00 


.00 


2.54 


4.00 


1.85 


.24 


1.24 


.41 


.00 


.00 


10.29 


1910-11 


.00 


.00 


.00 


1.05 


.74 


.20 


2.86 


3.54 


2.07 


.80 


.01 


Tr. 


11.27 


1911-12 


.19 


.00 


.35 


.45 


.02 


1.54 


.77 


.00 


4.80 


2.29 


.54 


.44 


11.39 


1912-13 


.02 


.24 


.00 


.82 


.48 


.04 


1.52 


3.02 


.65 


.13 


.12 


.13 


7.17 


1913-14 


.14 


.15 


.00 


.00 


2.59 


1.06 


3.78 


2.05 


.57 


1.29 


.14 


.09 


11.86 


1914-15 


.00 


.00 


.06 


.87 


.75 


2.75 


4.38 


3.16 


.89 


1.77 


1.13 


.00 


15.76 


27-year means 


.06 


.05 


.12 


.51 


.96 


1.73 


2.26 


2.10 


1.99 


.62 


.41 


.07 


10.88 



Descanso (37) ; elevation, 3,400 feet. 

[Authority, U. S. Weather Bureau.] 



13-year means. .. 



oO.OO 
.30 
.62 
.15 
.15 
.00 
Tr. 
.45 



.00 
.72 
.77 
.00 
.00 
.60 



60.00 
1.38 
.04 
.83 
.38 
Tr. 
.78 
.00 



2.62 
.00 
.00 
.30 
.57 
.00 



21 .53 



oTr. 
.03 
.56 
.00 
.00 
.25 
Tr. 



.00 
.36 
.23 
.00 
1.27 
.00 

.21 



a0.38 
2.71 
2.83 

.00 
1.62 

.63 
1.25 



.00 
1.86 

.57 
1.50 

.06 
1.57 

1.15 



o4.37 
2.12 
.40 
.35 
.25 
6.50 
.87 



5.12 

2.26 

.00 

.30 

3.42 

.97 

2.07 



al.00 
2.43 
2.90 
1.00 
1.06 
.15 
.12 



7.79 
.80 

2.35 
.00 

1.59 

4.82 

2.00 



2.93 
6.48 
5.28 
3.49 
4.00 
3.25 
4.47 



11.03 
6.06 
4.62 
.65 
3.27 
7.64 



0.10 
6.27 

.89 
1.69 

.75 
11.00 
4.52 



6.53 
1.36 
6.22 
.00 
6.65 
3.76 
9.05 

4.02 



8.04 
5.21 
4.11 
2.73 
1.25 
1.40 
8.00 



4.97 
4.01 
2.73 

13.84 
2.62 
1.78 
2.02 

4.44 



1.14 
.16 
.90 
.25 

4.25 
.57 

1.50 



.58 
2.08 
3.83 

.60 
2.83 
4.50 

1.79 



0.17 
.21 
2.35 
1.45 
2.69 
1.53 
.06 



.00 
.00 
.00 

1.04 
.40 
.22 

4.75 

1.14 



0.00 
.01 
.00 
.00 
.06 
.00 
.00 



.00 
.00 
.00 
.12 
.38 
.32 
.00 

.07 



18.13 
27.31 
20.88 
11.94 
16.46 
25.28 
21.57 



27.54 
21.65 
23.40 
16.02 
23.46 
37.16 

22.35 



a Estimated. 



b See Water-Supply Paper 81, U. S. Geological Survey. 



300 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

Valley Center (38); elevation, 1,360 feet. 

[Authorities: 1872 to 1898-99, S. G. Antony; 1911 to 1914-15, Volcan Land & Water Co.; 
W. S. Post, Engineer.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1872-73 


























11.65 


1873-74 
























37.80 


1874-75 
























13.30 


1875-76 
























19.40 


1876-77. . . 






1 
















8.80 


1877-78. . . . 
























26.51 


1878-79 























8.4 9 
24.55 


1879-80 























1880-81 








i 1 














16.03 


1881-82 






















16.61 


1882-83 1 






















11.94 


1883-84... | 






















50.50 


1884-85 




















13.36 


1885-86 | 




















30.55 


1886-87. . . 




















13.71 


1887-88 



















22.80 


1888-89 . 


















26. 50 


1889-90. . . 


















30.48 


1890-91 


















26.56 


1891-92 


















18.07 


1892-93. . . 

















20.60 


1893-94 













1 








9.90 


1894-95 














1 








24.70 


1895-96... 






















11.94 


1896-97 






.. 








1 








24.00 


1897-98. . . 




















10.93 


1898-99. . . 



























11.74 


1911-12 

1912-13 


a0.09 


aO.OO 


oO.Ol 


o0.04 


a0.08 


a0.79 


o0.56 
1.90 
7.08 
8.17 

5.27 


0.00 
3.80 
6.22 
6.41 

4.21 


6.50 

.88 

1.64 

1.61 

3.25 


3.00 

.66 

1.48 

4.12 

2.87 


1.20 
.23 
.27 

1.43 

.97 


a0.06 
.23 
.30 
Tr. 

.12 


12.33 


1913-14 


.18 
Tr. 

.09 


Tr. 

.00 

.00 


.01 
Tr. 

.00 


.05 
1.25 

.45 


2.40 
1.73 

1.40 


1.18 
3.15 

1.71 


20.81 


1914-15 

Means 


27.87 
19.74 



San Diego (39); elevation, 93 feet. 

[Authority, TJ. S. Weather Bureau.] 



1849-50 














0.00 


1.13 


1.00 


0.09 


0.00 


0.68 




1850-51 


0.00 


0.00 


0.00 


0.19 


2.82 


1.93 


.03 


1.51 


.34 


.87 


.71 


.01 


8.41 


1851-52 


.00 


.00 


.02 


.01 


.25 


3.74 


.58 


1.84 


1.87 


.85 


.32 


.00 


9.48 


1852-53 


.00 


.40 


.00 


.06 


1.45 


4.50 


.50 


.20 


1.52 


.25 


2.10 


.05 


11.03 


1853-54 


.00 


.21 


.00 


.00 


1.28 


1.77 


.99 


2.56 


1.88 


.89 


.18 


.01 


9.77 


1854-55 


.07 


1.36 


.09 


.27 


.04 


3.29 


1.97 


3.59 


1.30 


1.52 


.06 


.00 


13.56 


1855-56 


.00 


.04 


.00 


.11 


2.15 


.41 


1.27 


1.86 


1.59 


2.17 


.29 


.00 


9.89 


1856-57 


.00 


.00 


.07 


.00 


1.22 


1.30 


.26 


1.76 


.00 


.04 


.08 


.03 


4.76 


1857-58 


.00 


.02 


.01 


.49 


2.16 


1.30 


1.52 


.44 


1.24 


.17 


.00 


.19 


7.54 


1858-59 


.00 


.04 


.10 


.47 


.28 


3.10 


.00 


1.89 


.20 


.36 


.17 


.00 


6.61 


1859-60 


.02 


.00 


.00 


.18 


1.49 


1.79 


.72 


1.49 


.15 


.65 


.04 


.05 


6.58 


1860-61 


.14 


.00 


.00 


.00 


2.88 


2.99 


.82 


.79 


.05 


.04 


.00 


.19 


7.90 


1861-62 


.00 


.00 


1.59 


.05 


1.19 


3.20 


5.56 


1.39 


.97 


1.05 


.16 


.48 


15.64 


1862-63 


.11 


.00 


.00 


.89 


.05 


.93 


.32 


1.09 


.33 


.13 


.02 


.00 


3.87 


1863-64 


.00 


.00 


.36 


.00 


.73 


.04 


.04 


2.50 


.20 


.01 


1.25 


.01 


5.14 


1864-65 


.11 


.00 


.00 


.04 


2.41 


1.04 


1.28 


3.00 


.00 


.56 


.00 


.01 


8.45 


1865-66 


1.29 


.00 


.00 


.02 


.52 


.84 


5.05 


3.43 


1.47 


.11 


.09 


.00 


12.82 


1866-67 


.00 


.10 


.00 


.00 


.24 


1.82 


2.32 


.85 


7.88 


.48 


.04 


.00 


13.73 


1867-68 


.00 


.30 


.00 


.34 


.45 


3.06 


3.37 


1.63 


.73 


1.20 


.15 


.00 


11.23 


1868-69 


.51 


.00 


.05 


.00 


2.00 


1.52 


2.88 


1.88 


1.98 


.53 


.33 


.00 


11.68 


1869-70 


.05 


.00 


.00 


.05 


2.32 


.94 


.54 


.77 


.33 


.20 


.28 


.00 


5.48 


1870-71 


.04 


.07 


.00 


1.54 


.18 


.42 


.52 


1.35 


.01 


.70 


.34 


.00 


5.17 


1871-72 


.00 


.00 


.00 


.00 


1.33 


1.39 


.99 


2.63 


.46 


.26 


.12 


.00 


7.18 


1872-73 


.00 


.18 


.00 


.00 


.00 


1.43 


.44 


4.21 


.11 


.10 


.03 


.00 


6.50 


1873-74 


.00 


1.95 


.00 


.00 


.77 


5.46 


3.11 


3.73 


1.20 


.34 


.32 


.00 


16.88 


1874-75 


.12 


.00 


.13 


.53 


.88 


.55 


2.38 


.37 


.45 


.12 


.20 


.02 


5.75 


1875-76 


.00 


.21 


.39 


.00 


2.25 


.41 


2.47 


2.44 


1.78 


.06 


.05 


.05 


10.11 


1876-77 


.03 


.06 


.03 


.08 


.04 


.1.5 


1.05 


.18 


1.44 


.26 


.43 


Tr. 


3.75 


1877-78 


.00 


.00 


.00 


.81 


.06 


3. 89 


1,45 


4.83 


1.41 


2.91 


.58 


.16 


16.10 


1878-79 


.00 


.00 


.00 


.96 


.00 


1.57 


3.54 


1.04 


.10 


.60 


Tr. 


.07 


7.88 


1879-80 


.00 


.00 


.00 


.29 


2.77 


6.30 


.61 


1.50 


1.43 


1.34 


.06 


.06 


14.36 


1880-81 


.09 


.32 


.00 


.53 


.28 


4.15 


.52 


.45 


1.88 


1.35 


.04 


.05 


9.66 


1881-82 


.00 


.01 


.04 


.24 


.12 


.30 


4. 53 


2.55 


1.02 


.45 


.18 


.07 


9.51 


1882-83 


.00 


Tr. 


.01 


.41 


.39 


.13 


1.09 


.95 


.41 


.31 


1.14 


.08 


2.94 



a Estimated. 



DETAILED PRECIPITATION" RECORDS. 



301 



Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

San Diego (39): elevation, 93 feet— Continued. 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1883-84 


.00 


.00 


.00 


2.01 


.20 


1.82 


1.34 


9.05 


6.23 


2.84 


2.17 


.31 


25.97 


1884-85 


.00 
Tr. 


Tr. 
.13 


.07 
Tr. 


.35 
.31 


.11 
1.56 


5.12 
.71 


.35 
6.95 


.02 
1.51 


.78 
3.73 


1.20 
1.95 


.61 
.04 


.06 
.07 


8.67 


1885-86 


16.96 


1886-87 


Tr. 


Tr. 


.00 


.05 


.95 


.10 


.04 


4.51 


.02 


2.14 


.47 


.04 


8.32 


1887-88 


.01 
.01 
Tr. 


Tr. 
Tr. 
.04 


Tr. 
.04 
Tr. 


Tr. 
.26 
2.12 


2.08 

1.83 

.12 


1.14 
2.84 
7.71 


1.96 
1.72 
2.79 


1.48 
1.80 
1.70 


2.79 

2.20 

.41 


.10 
.19 
.05 


.22 

.03 
.08 


.04 
.10 
.00 


9.82 


1888-89 , 


11.02 


1889-90 


15.02 


1890-91 


.00 
Tr. 


Tr. 
.00 


.65 
.08 


.01 

.04 


.72 
.10 


1.61 
1.29 


1.21 

1.58 


4.84 
2.96 


.27 
.96 


.76 
.41 


.35 
1.15 


.05 
.13 


10.47 


1891-92 


8.70 


1892-93 


.00 
Tr. 


.05 
.00 


Tr. 
.00 


.22 
.11 


.91 
.91 


L91 


.78 
.29 


.47 
.49 


5.50 
1.05 


.22 
.11 


.39 
.09 


Tr. 
.01 


9.26 


1893-94 


4.97 


1894-95 


.00 


.04 


.01 


Tr. 


.00 


2.26 


7.33 


.53 


1.43 


.11 


.19 


.00 


11.90 


1895-96 


.00 


.00 


.01 


.27 


1.19 


.27 


1.27 


.02 


2.89 


.25 


.03 


.01 


6.21 


1896-97 


Tr. 


.13 


Tr. 


.97 


.98 


2.18 


3.13 


2.72 


1.53 


.02 


.12 


Tr. 


11.78 


1897-98 


.01 


Tr, 


Tr. 


1.06 


.02 


.32 


1.71 


.06 


.91 


.22 


.66 


.02 


4.99 


1898-99 


.00 


.00 


.07 


.00 


.15 


.87 


2.34 


.30 


.85 


.29 


.10 


.27 


5.24 


1899-1900 


.00 


.07 


.00 


.35 


.86 


.65 


.69 


.03 


.53 


1.26 


1.45 


.08 


5.97 


1900-1901 .-.. 


.00 
Tr. 


Tr. 
Tr. 


Tr. 

.06 


.30 
.28 


1.43 
.41 


.00 
.02 


2.08 
1.70 


4.77 
1.57 


1.07 
1.86 


.01 
.21 


.77 
.06 


.02 
Tr. 


10.45 


1901-2 


6.17 


1902-3 


.92 
.00 
.00 


Tr. 
Tr. 
Tr 


Tr. 
Tr. 
Tr. 


.06 
.07 
.17 


1.53 
Tr. 
.00 


3.58 

.35 

2.46 


.69 

.04 

2.16 


2.27 
1.50 
5.90 


1.17 
2.17 
2.98 


1.40 
.15 
.30 


.14 
.12 
.35 


Tr. 
.00 
Tr. 


11.76 


1903-4. 


4.40 


1904-5 


14.32 


1905-6 


.16 


.00 


.50 


.25 


3.38 


.38 


.98 


2.62 


4.68 


.98 


.72 


.03 


14.68 


1906-7 


Tr. 


.10 


.12 


.03 


.62 


4.02 


3.27 


.45 


1.62 


.13 


.07 


.19 


10.62 


1907-8 


.03 


.00 


.00 


1.71 


.05 


.43 


2.80 


2.41 


.61 


.35 


.16 


.00 


8.55 


1908-9 


.00 


.64 


.20 


.15 


1.00 


.27 


3.57 


1.76 


2.62 


.02 


Tr. 


Tr. 


10.23 


1909-10 


Tr. 


Tr. 


.02 


.00 


2.39 


3.76 


2.00 


.19 


1.30 


.08 


.05 


.00 


9.79 


1910-11 


.01 


.05 


.17 


1.35 


.40 


.15 


3.35 


4.92 


.92 


.65 


.01 


.01 


11.99 


1911-12 


.12 


.00 


.10 


.28 


.02 


1.39 


.66 


.00 


5.72 


2.13 


.17 


.16 


10.72 


1912-13 


.14 


.26 


.00 


.89 


.40 


.03 


1.19 


2.40 


.42 


.08 


.07 


.09 


5.97 


1913-14 


.06 


.02 


.02 


Tr. 


2.23 


.72 


3.59 


1.90 


.36 


.85 


.08 


.00 


9.83 


1914-15 


.00 


.00 


Tr. 


1.05 


.86 


2.21 


4.91 


3.62 


.33 


1.15 


.28 


Tr. 


14.41 


65-year means 


.06 


.10 


.08 


.36 


.96 


1.80 


1.86 


1.99 


1.48 


.64 


.32 


.05 


9.69 



El Cajon (40) ; elevation, 570 feet. 

[Authority, IT. S. Weather Bureau.] 



1875-76 










1.99 
.14 


1.01 
.07 


3.83 


2.71 


2.53 

1.00 

1.15 

.71 


0.11 
.40 
.08 

1.30 


0.02 


0.02 




1876-77 


0.07 










1899 








2.15 
1.33 


.55 
.11 


.04 
1.48 


.52 
.19 




1899-1900 


00 


Tr. 


0.00 


0.67 


1.39 


.87 


8.05 


1900-1901 


.00 


.00 


Tr. 


.40 


2.61 


.00 


1 89 


2.66 


2 57 


.69 


.67 


.11 


11 60 


1901-2 


.10 


.11 


.00 


.32 


.28 


.43 


2.28 

84 


2 49 


2 81 


33 


.04 


.00 
Tr 


9.19 
11.46 

5.71 
20.50 
18.62 


1902-3 


.75 


.00 


.00 


.20 


1 73 


2 21 


2 97 


1 33 


1.29 
.10 
.36 

1.66 


14 


1903-4 


.00 


.00 


Tr. 


.20 


00 


10 


.17 

2.67 
1.20 


2 19 


2.66 
4.23 
6.56 


29 


.00 
.00 
.04 


1904-5 


.00 


Tr. 


Tr. 


.27 


00 


2 73 


9 22 


1 02 


1905-6 


.03 


.01 


.57 


.25 


4.89 


.55 


2.13 


.73 


1906-7 


Tr. 


.13 


.30 


Tr. 


1.52 


4.14 


4.35 


.85 


3.06 


.44 


.20 


.25 


15.24 


1907-8 


.00 


.00 


.00 


2.10 


.62 


.57 


4.58 


3.39 


1.34 


.69 


.23 


.00 


13.52 


1908-9 


.16 


.89 


.32 


.59 


.84 


1.19 


5.31 


2.83 


3.37 


.00 


.00 


.00 


15.50 


1909-10 


.00 


.15 


.00 


.00 


2.87 


4.75 


2.72 


.35 


2.21 


.24 


.00 


.00 


13.29 


1910-11 


.34 


.00 


.15 


.94 


.88 


.33 


4.74 


4.00 


1.30 


1.07 


.00 


.00 


13.75 


1911-12 


.06 


.00 


.46 


.28 


.00 


1.59 


.50 


.00 


7.80 


2.42 


1.29 


.70 


15.10 


1912-13 


.00 


.32 


.00 


.77 


.76 


.05 


1.50 


3.10 


1.09 


.19 


.16 


.10 


8.04 


1913-14 


.20 


.33 


.00 


.02 


2.83 


1.03 


4.56 


4.00 


.60 


1.25 


.27 


.16 


15.25 


1914-15 


.00 


.00 


.10 


1.09 


1.35 


2.85 


6.49 


4.22 


1.33 


2.86 


1.42 


.00 


21.71 


16-year means 


.10 


.12 


.12 


.51 


1.41 


1.46 


2.82 


2.78 


2.69 


.93 


5.00 


1.00 


13.53 



Lakeside (41); elevation, 500 feet. 

[Authority, San Diego & Southeastern Ry. Co.] 



1909-10 

1910-11 

1911-12 

1912-13 

1913-14 

1914-15 

6-year means. 



0.00 
.00 
.00 
.00 
.00 
.00 

.00 



0.00 
.00 
.00 
.22 
.04 
.00 

.04 



0.00 
.00 
.50 
.00 
.00 
.03 



0.00 
.75 
.15 
.62 
.00 

1.03 

.42 



3.06 
1.00 
.00 
.00 
2.62 
1.60 

1.38 



3.96 
.43 

1.72 
.00 

1.06 

3.04 

1.70 



3.76 
3.56 
.50 
1.87 
4.46 
5.82 

3.33 



0.35 
4.95 
.00 
3.37 
3.02 
3.98 

2.61 



1.72 
1.38 
6.77 
.98 
.54 
1.12 

2.09 



0.10 
.77 

3.22 
.43 

1.24 

2.17 

1.32 



0.00 
.00 
.85 
.20 
J19 

1.82 

.51 



0.00 
.00 
.70 
.04 
.02 
.00 

.13 



302 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

End of flume near La Mesa (42); elevation, 640 feet. 

[Authority, Cuyamaca Water Co., W. S. Post, engineer.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1899-1900 

1900-1901 

1901-2 

1902-3 

1903-4 

1904-5 

1905-6 

1906-7 

1907-8 

1908-9 

1909-10 

1910-11 


0.00 
.00 
.00 
.86 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.47 
.27 
.00 
.20 
.00 

.11 


0.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.90 
.18 
.00 
.00 
.24 
.00 
.00 

.08 


0.00 
.01 
.00 
.00 
.03 
.00 
.35 
.42 
.00 
.41 
.00 
.00 
.10 
.00 
.00 
.03 

.08 


0.62 
.31 
.39 
.20 
.04 
.23 
.12 
.00 

1.07 
.07 
.02 
.99 
.24 
.44 
.00 

1.28 

.38 


1.35 

2.76 

.37 

2.17 

.00 

.00 

3.08 

1.35 

.40 

.11 

3.06 

1.10 

.05 

.46 

3.79 

1.06 

1.32 


0.81 
.00 
.27 

2.70 
.10 

3.21 
.65 

4.91 
.66 
.73 

5.83 
.25 

1.53 
.00 

1.07 

3.36 

1.57 


1.28 
2.90 
2.44 
1.07 

.18 
2.69 
1.35 
4.40 
3.57 
5.47 
2.38 
4.57 

.74 
1.70 
4.30 
7.34 

2.89 


0.00 
6.06 
2.90 
2.77 
1.83 
7.76 
2.08 

.96 
3.46 
2.99 

.22 
4.72 

.00 
3.21 
3.72 
6.53 

3.08 


0.70 
.70 
2.24 
1.83 
3.00 
4.05 
6.64 
3.24 
1.35 
3.10 
1.80 
1.41 
7.58 
1.12 
.53 
1.86 

2.57 


1.39 
.75 
.20 

1.53 
.12 
.42 

1.78 
.31 
.82 
.05 
.45 

1.27 

2.66 
.21 

1.61 

2.94 

1.03 


1.45 
.19 
.17 
.04 
.23 

1.23 
.63 
.20 
.42 
.05 
.00 
.00 
.59 
.29 
.20 

1.61 

.45 


0.00 
.00 
.00 
.00 
.00 
.00 
.00 
.35 
.00 
.00 
.00 
.06 
.42 
.11 
.11 
.00 

.06 


7.60 
13.68 

8.98 
13.17 

5.53 
19.59 
16.68 
16.14 
11.75 
13.88 
13.94 
14.84 


1911-12 

1912-13 

1913-14 

1914-15 

16-year means 


14.18 

7.78 

15.53 

26.01 

13.69 



Los Coches Creek (43); elevation, 710 feet. 

[Authority, Cuyamaca Water Co., W. S. Post, engineer.] 



1900-1901 












9.34 








0.50 


0.47 


0.00 


10.31 


1901-2 


0.02 


0.00 


0.00 


0.22 


0.32 


.08 


2.35 


2.03 


3.44 


.49 


.06 


.00 


9.01 


1902-3 


.61 


.00 


.00 


.40 


1.73 


2.38 


1.13 


3.20 


1.96 


1.21 


.05 


.00 


12.67 


1903-4 


.00 


.00 


.13 


.19 


.00 


.12 


.25 


2.35 


2.53 


.20 


.75 


.00 


6.52 


1904-5 


.00 


.00 


.00 


.51 


.00 


1.98 


2.52 


9.77 


4.70 


.46 


1.03 


.00 


20.97 


1905-6 


.00 


.00 


.93 


.25 


4.08 


.60 


1.23 


1.98 


6.36 


1.56 


.83 


.01 


17.83 


1906-7 


.00 


.04 


.35 


.05 


2.09 


5.78 


4.58 


.93 


2.69 


.16 


.16 


.12 


16.95 


1907-8 


.00 


.00 


.00 


1.44 


.56 


.48 


3.98 


3.44 


1.48 


.68 


.19 


.00 


12.25 


1908-9 


.00 


.52 


.65 


.53 


.65 


1.38 


4.01 


2.77 


2.50 


.06 


.03 


.00 


13.10 


1909-10 


.00 


.27 


.00 


.03 


3.17 


4.78 


2.25 


.43 


2.15 


.10 


.00 


.00 


13.18 


1910-11 


.10 


.00 


.03 


.68 


.99 


.43 


4.18 


3.71 


1.19 


.65 


.00 


.00 


11.96 


1911-12 


.00 


.00 


.08 


.28 


.06 


1.44 


.47 


.00 


6.94 


2.62 


1.20 


.54 


13.63 


1912-13 


.00 


.38 


.00 


.74 


.58 


.00 


1.57 


3.47 


.87 


.22 


.26 


.22 


8.31 


1913-14 


.10 


.22 


.01 


.04 


2.80 


.89 


4.80 


4.10 


.74 


1.32 


.16 


.12 


15.30 


1914-15 


.00 


.00 


.09 


1.03 


1.60 


2.96 


6.43 


5.91 


1.38 


2.62 


1.34 


.00 


23.36 


15-year means 


.06 


.10 


.16 


.45 


1.33 


1.67 


2.84 


3.15 


2.79 


.88 


.43 


.07 


13.69 



Chocolate Creek (44); elevation, 760 feet. 

[Authority, Cuyamaca Water Co., W. S. Post, engineer.] 



1899-1900 


0.00 


0.00 


0.00 


0.00 


0.00 


1.00 


2.99 


0.00 


0.96 


2.06 


1.65 


0.00 


8.66 


1900-1901 


.00 


.00 


.00 


.15 


4.08 


.00 


2.88 


8.08 


1.20 


.60 


.63 


.00 


17.62 


1901-2 


.00 


.00 


.00 


.00 


.40 


.05 


3.19 


2.26 


4.33 


.85 


.06 


.00 


11.14 


1902-3 


.36 


.00 


.00 


.35 


1.95 


2.21 


1.78 


4.08 


2.03 


1.45 


.06 


.00 


14.27 


1903-4 


.00 


.00 


.14 


.17 


.00 


.00 


.30 


2.87 


3.65 


.40 


.24 


.00 


7.77 


1904-5 


.00 


.00 


.00 


.52 


.00 


2.04 


4.07 


9.61 


5.76 


.44 


1.32 


.00 


23.76 


1905-6 


.00 


.oo 


.81 


.07 


3.38 


1.15 


1.96 


4.43 


8.68 


1.59 


1.30 


.05 


23.42 


1906-7 


.00 


.25 


.49 


.05 


1.96 


5.98 


5.39 


1.53 


3.41 


.62 


.23 


.43 


20.34 


1907-8 


.00 


.00 


.00 


1.92 


1.18 


.71 


4.16 


4.73 


2.11 


1.38 


.47 


.00 


16.66 


1908-9 


.00 


.67 


.64 


1.20 


.80 


.69 


8.17 


4.42 


3.36 


.22 


.05 


.00 


20.22 


1909-10 


.00 


.89 


.00 


.00 


3.55 


6.56 


2.79 


.87 


2.48 


.33 


.00 


.00 


17.47 


1910-11 


.31 


.00 


.28 


.80 


1.37 


.66 


4.38 


4.20 


1.37 


1.29 


.00 


.00 


14.66 


1911-12 


.00 


.00 


.12 


.30 


.10 


1.84 


.53 


.00 


9.75 


3.10 


1.67 


.50 


17.91 


1912-13 


.04 


.63 


.00 


1.05 


.80 


.00 


2.38 


5.03 


1.43 


.49 


.36 


.22 


12.43 


1913-14 


.05 


.12 


.00 


.04 


3.13 


1.86 


5.50 


5.22 


.97 


2.47 


.20 


.17 


19.73 


1914-15 


.00 


.00 


.06 


1.09 


1.22 


3.07 


6.51 


7.56 


1.45 


3.89 


2.20 


.00 


27.05 


16-year means 


.05 


.16 


.16 


.48 


1.49 


1.74 


3.56 


4.05 


3.31 


1.35 


.65 


.08 


17.07 



DETAILED PRECIPITATION RECORDS. 



303 



Table 64.- 



-Monthly and annual precipitation at 106 stations in or near San Diego 
County — Continued. 

Diverting dam (45); elevation, 820 feet. 

[Authority, Cuyamaca Water Co., W. S. Post, engineer.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1899-1900 


0.00 


0.00 


0.00 


0.80 


1.65 


0.90 


3.95 


0.05 


0.37 


1.62 


1.18 


0.00 


10.52 


1900-1901... 


.00 


.00 


.00 


.07 


4.33 


.00 


2.72 


6.69 


1.28 


.44 


1.03 


.00 


16.56 


1901-2 


.00 


.03 


.00 


.25 


.37 


.00 


2.70 


2.26 


4.22 


.78 


.02 


.00 


10.63 


1902-3 


.40 


.00 


.00 


.35 


2.24 


2.11 


1.21 


4.37 


3.20 


2.25 


.08 


.00 


16.21 


1903-4 


.00 


.00 


.19 


.11 


.00 


.00 


.27 


2.23 


3.76 


.30 


.23 


.00 


7.09 


1904-5 


.00 


.00 


.00 


.25 


.00 


1.30 


2.97 


10.06 


6.55 


.95 


2.38 


.00 


24.46 


1905-6 


.00 


.00 


.38 


.23 


3.43 


.98 


2.21 


4.20 


11.87 


1.75 


1.32 


.00 


26.37 


1906-7 


.11 


.95 


.66 


.64 


2.19 


7.10 


6.01 


1.71 


4.07 


.40 


.19 


.34 


24.37 


1907-8 


.00 


.00 


.00 


2.74 


.26 


.50 


4.08 


3.99 


1.84 


.99 


.65 


.00 


15.05 


1908-9 


.00 


.58 


.57 


.35 


.62 


.93 


5.71 


4.50 


3.06 


.06 


.00 


.00 


16.38 


1909-10 


.52 


.68 


.00 


.00 


2.82 


5.93 


3.41 


.51 


2.68 


.30 


.00 


.00 


16.85 


1910-11 


.11 


.00 


.28 


1.10 


1.62 


.75 


5.40 


4.09 


1.47 


1.10 


.00 


.00 


15.92 


1911-12 


.00 


.00 


.13 


.30 


.10 


1.13 


.44 


.00 


10.13 


3.29 


1.84 


.53 


17.89 


1912-13 


.03 


.36 


.00 


1.05 


.61 


.00 


2.36 


3.91 


1.40 


.19 


.19 


.08 


10.18 


1913-14 


.11 


.11 


.11 


.04 


2.99 


1.11 


5. 69 


4.11 


.81 


2.32 


.34 


.20 


17.94 


1914-15 


.02 


.00 


.00 


1.30 


1.09 


3.34 


6.62 


6.35 


1.65 


2.86 


2.30 


.00 


25.53 


16-year means 


.08 


.17 


.14 


.59 


1.52 


1.63 


3.59 


3.69 


3.65 


1.22 


.74 


.07 


16.99 



East Cuyamaca (46) ; elevation, 4,600 feet. 

[Authority, Cuyamaca Water Co., W. S. Post, engineer.] 



1912-13 

1913-14 

1914-15 

3-year means . 



o0.42 
.72 
.00 


a0.32 
.21 
.46 


aTr. 

2.10 

.43 


o2.76 
.22 
.46 


ol. 20 
3.18 
1.38 


0.04 
1.75 
3.53 


»2.52 
4.86 
8.74 


6.20 
5.16 
6.81 


1.86 
1.05 
1.01 


1.03 

.77 
3.22 


0.22 

.50 

2.44 


0.13 
.10 
.00 


.38 


.33 


.84 


1.15 


1.92 


1.77 


5.37 


2.72 


1.31 


1.67 


1.05 


.08 



Schilling (47) ; elevation, 4,550 feet. 

[Authority, Cuyamaca Water Co., W. S. Post, engineer.] 



1912-13 

1913-14 

1914-15 

3-year means . 



ao.42 
.86 
.00 

.43 



a0.32 
1.35 
.20 

.62 



<*Tr. 
.60 



.23 



02.76 
.14 
.83 

1.24 



O1.20 
5.66 
1.41 

2.76 



0.04 
2.46 
5.35 

2.62 



&1.06 
8.08 
11.09 

6.74 



5.61 
5.94 
9.83 

7.13 



ol.79 
1.68 



1.48 



1.05 
2.70 
4.94 

2.90 



0.51 

.17 

3.90 

1.53 



0.29 
.46 
.00 

.25 



Campo (48) ; elevation, 2,543 feet. 

[Authority, U. S. Weather Bureau.] 



1876-77 














2.42 


4.74 


2.29 


1.08 


0.91 


0.00 




1877-78 


0.50 


0.00 


0.00 


0.35 


1.50 


2.44 


1.79 


5.45 


1.84 


5.75 


.41 


.00 


20.03 


1878-79 


2.32 


.01 


.00 


.31 


.55 


1.29 


2.18 


1.32 


.60 


2.01 


.00 


.00 


10.59 


1879-80 


.00 


.00 


.00 


.00 


3.00 


2.23 


3.00 


2.15 


3.56 


4.00 


.00 


.00 


17.94 


1880-81 


.12 


.41 


.01 


.68 


.85 


4.85 


1.74 


.53 


5.00 


1.52 


.12 


.04 


15.87 


1881-82 


.07 


1.27 


.02 


.73 


.11 


.24 


3.10 


4.57 


1.01 


1.10 


.18 


.26 


12.66 


1882-83 


.62 


.53 


.02 


.46 


1.57 


2.59 
















1888-89 


2.42 


4.65 


4.00 


1.90 


.45 


.10 




1889-90 


.53 


2.50 


.50 


1.10 


1.67 


9.34 


2.40 


7.25 


1.69 


1.86 


.90 


.16 


29.90 


1890-91 


2.26 


2.67 


1.80 


.44 


.95 


2.80 


.00 


13.30 


.50 


1.20 


.75 


.00 


26.67 


1891-92 


.00 


16.10 


.00 


.00 


.25 


3.21 


.75 


4.55 


3.30 


1.25 


2.75 


.35 


32. 51 


1892-93 


.00 


.00 


.00 


.12 


.71 


.50 


3.55 


3.65 


7.19 


1.54 


.41 


.00 


17.67 


1893-94 


.00 


.00 


.57 


.11 


3.38 


2.08 


5.89 


5.83 


1.01 


.80 


4.38 


1.26 


25.31 


1894-95 


.00 
.24 
.00 


.00 
.60 

.00 


.25 

1.61 
.05 


.46 
1.15 

.28 


1.57 
2.65 

4.47 


2.59 
.10 
.00 
















1899-1900 


.55 
2.03 


2.07 

8.22 


1.04 
.69 


.10 
.54 








1900-1901 


1.18 


.00 


17.46 


1901-2 


.61 


.63 


.00 


1.02 


.43 


.23 


4.28 


4.72 


4.00 


1.33 


.07 


.12 


17.44 


1902-3 


2.24 


.00 


.00 


.03 


2.27 


3.04 


1.85 


4.93 


2.30 


3.23. 


.11 


Tr. 


20.00 


1903-4 


.00 


.00 


.47 


.03 


.00 


.00 


.41 


2.68 


4.19 


.49 


.52 


.00 


8.79 


1904-5 


.85 


1.59 


.64 


.13 


.00 


1.82 


4.32 


11.94 


6.87 


.92 


2.53 


.00 


31.61 


1905-6 


.00 


.25 


.68 


Tr. 


5.85 


1.12 


2.98 


3.69 


10.20 


1.60 


.70 


.00 


27.07 


1906-7 


.18 


2.12 


.90 


.10 


3.23 


7.15 


5.24 


1.67 


3.91 


.25 


.41 


.26 


25.42 


1907-8 


.00 


.00 


.00 


2.46 


.25 


.12 


4.21 


4.90 


1.91 


.71 


1.01 


.00 


15.57 


1908-9 


.26 


.00 


.40 


1.72 


.77 


1.83 


8.41 


5.43 


4.05 


.00 


.00 


.00 


22.87 



a Estimated. 



& Probably low. Shows actual catch of snow. 



304 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF, 



Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

Campo (48) ; elevation, 4,550 feet— Continued. 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dee. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1909-10 


.00 


.00 


.00 


.00 


3.44 


5.82 


4.93 


.66 


2.25 


.32 


.00 


.00 


17.42 


1910-11 


3.44 


.00 


1.94 


1.03 


1.12 


.15 


4.65 


5.70 


1.40 


.96 


.00 


.00 


20.39 


1911-12 


.40 


.00 


.00 


.00 


.10 


2.08 


.64 


.00 


10.67 


3.51 


1.52 


.15 


19.07 


1912-13 


.15 


.20 


.00 


.98 


.92 


.00 


2.75 


5.27 


1.90 


.33 


.13 


.20 


12.83 


1913-14 


.36 


1.77 


.00 


.05 


2.39 


1.49 


5.85 


4.07 


.92 


2.34 


.78 


.00 


20.02 


1914-15 


.75 


.00 


.22 


.88 


.76 


3.99 


6.36 


4.47 


1.74 


1.50 


2.56 


.00 


23.23 


25-year means 


.60 


1.18 


.33 


.50 


1.56 


2.31 


3.33 


4.68 


3.31 


1.56 


.86 


.11 


20.33 



Buckman Springs (49); elevation, 5,450 feet (?). 
[Authority, Cuyamaca Water Co., W. S. Post, engineer.] 



1914-15. 



.70 



00 



68 



.91 .68 5 



8.76 6.55 1.67 1.73 4.89 .00 31 



Morena dam (50); elevation, 3,000 feet. 

[Authority, Southern California Mountain Water Co.] 



1906-7 














6.44 
5.61 


1.59 

4.98 


4.71 
1.90 


0.84 
1.18 


0.39 
.92 


0.88 
.00 


18.25 


1907-8... 






0.00 


0.00 


0.00 


2.64 


0.41 


0.61 


1908-9... 






.00 


.86 


1.31 


1.29 


1.31 


1.20 


10.90 


5.55 


4.22 


.17 


.00 


.00 


26.81 


1909-10. . 






.06 


1.64 


.00 


.00 


3.99 


5.64 


5.69 


.98 


2.78 


.38 


.00 


.00 


21.16 


1910-11 . . 






.97 


.00 


.47 


1.36 


1.91 


.46 


4.33 


6.39 


2.04 


1.59 


.00 


.00 


19.52 


1911-12.. 






.96 


.00 


.06 


.71 


.14 


1.75 


1.09 


.06 


12.07 


3.59 


1.25 


.14 


21.82 


1912-13.. 






.43 


.30 


.00 


1.19 


1.18 


.48 


3.11 


4.86 


2.71 


.59 


.28 


.31 


15.44 


1913-14.. 






.43 


1.64 


.26 


.00 


2.40 


2.00 


5.54 


4.76 


1.02 


1.94 


.41 


.27 


20. 6? 


1914-15.. 






.00 


.00 


.10 


1.38 


.61 


4.26 


8.00 


5.78 


2.34 


4.08 


4.13 


.00 


30.68 


8-year means 


.36 


.56 


.25 


1.07 


1.49 


2.05 


5.53 


4.17 


3.64 


1.69 


.87 


.09 


21.79 



La Jolla Indian Reservation (51) ; elevation, 3,800 feet. 

[Authority, U. S. Weather Bureau.] 



1911-12 


a0.80 


oO.OO 


a0.40 


a0.40 


a0.10 


o2.00 


1.18 


Tr. 


12.05 


4.73 


2.10 


0.05 


23.81 


1912-13 


.18 


.96 


.00 


2.35 


1.33 


.78 


3.02 


7.64 


2.67 


1.43 


.73 


.62 


21.71 


1913-14 


.14 


.60 


.14 


.05 


3.41 


3.46 


10.08 


8.97 


2.45 


3.18 


.10 


.94 


33.52 


1914-15 


.00 


.00 


.00 


2.23 


1.19 


4.56 


11.05 


11.94 


3.48 


6.90 


4.63 


.00 


45.98 


4-year means 


.28 


.39 


.14 


1.26 


1.51 


2.70 


6.33 


7.14 


5.16 


4.06 


1.89 


.40 


31.26 



Laguna (52) ; elevation, 5,440 feet. 

[Authority, Arch. Campbell. Copied from U. S. Geological Survey records.] 



1884-85... 




















2.10 


1.36 


0.17 





1885-86 


0.00 
.21 


1.87 
2.43 


"6.66" 


0.44 
.29 


2.71 
1.40 


0.60 












1S86-87.. 














1890-91 












.60 

.45 

.25 

.00 

44 

.00 

2.19 

2.09 

.11 

.54 

.50 


.00 
.00 
.00 
.00 
.00 
.00 
.30 
.00 
.21 
.15 
.00 




1894-95 

1895-96 


1.15 
.00 

1.50 
.00 
.00 
.00 
.00 
.42 

2.32 
.00 

1.67 


2.83 
.00 

3.83 
.00 
.00 
.00 
.00 

1.25 
.00 
.45 

6.95 


.00 
.00 
.00 
.03 
.00 
.00 
.20 
.00 
.00 
1.08 
.21 


.00 

T35" 
2.50 
.00 
1.85 
.40 
1.42 
.48 
.00 
.57 


.00 
6.40 
2.48 

.00 
o.OO 
2.70 
6.20 

.54 
3.23 

.00 

.00 


9.97 

2.74 

1.80 

o.OO 

1.65 

.00 

.35 

2.95 

.05 


17.44 
3.55 


2.87 


2.70 

5.60 

.00 

00 
1.00 
.95 
6.15 

00 


.00 

1.55 

.00 

4. 

3.80 
.71 
1.05 
3.20 
2.00 


37.41 
17.35 


1896-97 

1897-98 


3.60 | 1.08 
8.10 


18.58 
16.87 


1898-99 

1899-1900 

1900-1901 

1901-2 

1902-3 

1903-4 

1904-5 


3.30 

5.60 

.40 

.55 


16 

.37 

8.60 

.35 

&2.00 

06. 


16.00 
17.16 
24.75 
12.25 

14.87 
10.63 


1914-15 




13.10 
4.00 


6.50 
2.54 


.68 
2.«8 


8.40 

1.85 


.54 

.84 


.00 

.06 




10-year means 


.54 


.84 


.13 


1.21 


1.73 


2.16 


18.59 



a Estimated. 



DETAILED PRECIPITATION RECORDS. 



305 



Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

Barrett dam (53); elevation, 1,600 feet. 

[Authority, Southern California Mountain Water Co.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1908-9 














6.88 
4.39 
3.01 
.48 
2.44 
4.28 
11.05 

4.27 


4.71 
.76 

5.34 
.07 

5.04 

4.37 
11.94 

4.59 


3.83 
2.13 
1.54 
10.93 
1.91 
.78 
3.48 

3.46 


0.04 
.28 
.69 

3.30 
.35 

1.72 

6.90 

2.21 


0.00 
.00 
.00 

1.25 
.18 
.38 

4.63 

1.07 


0.00 
.00 
.00 
.08 
.21 
.11 
.00 

.07 




1909-10 

1910-11 

1911-12 

1912-13 

1913-14 

1914-15 

6- year means 


0.00 
.53 
.68 
.05 
.26 
.00 

.25 


1.07 
.00 
.00 
.11 
.63 
.00 

.30 


0.00 
.53 
.06 
.00 
.75 
.00 

.22 


0.00 
1.03 
.34 
.81 
.00 
2.23 

.74 


3.10 
1.10 
.08 
.62 
1.80 
1.19 

1.32 


4.91 
.55 

1.70 
.05 

1.17 

4.56 

2.16 


16.64 
14.32 
18.97 
11.77 
16.25 
45.98 

20.66 



Jamul Store (54) ; elevation, 1,040 feet. 

[Authority, city of San Diego.] 



1914-15. 



0.00 0.00 0.11 0.92 1.15 3.13 6.57 4.85 1.49 2.70 



El Cajon Valley— Sweetwater Pass (55) ; elevation, 670 feet. 

[Authority, Cuyamaca "Water Co., "W. S. Post, engineer.] 



1908-9 


0.00 


0.71 


0.21 


0.89 


0.82 


1.67 


3.14 


2.30 


3.08 


0.00 


0.06 


0.00 


12.88 


1909-10 


.00 


.09 


.00 


.00 


2.81 


4.17 


1.95 


.20 


1.69 


.16 


.00 


.00 


11.07 


1910-11 


.22 


.00 


.10 


1.81 


.86 


.27 


3.59 


2.99 


.90 


.61 


.00 


.00 


11.35 


1911-12 


.00 


.00 


.52 


.18 


.05 


1.27 


.27 


.00 


.00 


1.97 


1.03 


.72 


6.01 


1912-13 


.00 


.25 


.00 


.86 


.41 


.00 


1.42 


2.78 


1.12 


.15 


.25 


.13 


7.37 


1913-14 


.15 


.14 


.02 


.02 


3.01 


.62 


4.73 


3.80 


.59 


1.26 


.31 


.09 


14.74 


1914-15 


.00 


.00 


.09 


1.21 


1.14 


3.13 


5.58 


5.28 


1.08 


2.33 


1.25 


.00 


21.09 


7-year means 


.05 


.17 


.13 


.71 


1.30 


1.59 


2.95 


2.48 


1.21 


.92 


.41 


.31 


12.07 



Pine Hills Hotel (56); elevation, 4,100 feet. 

[Authority, Volcan Land & "Water Co., "W. S. Post, engineer.] 



1913-14 

1914-15. , 

2-year means . . 



o0.40 
.67 



53 



1.45 
.00 



.72 



aO.OO 
30 



0.10 
1.85 



.97 



7. 80 2. 75 
1. 20 5. 96 



4.50 4.35 



10.20 
11.05 



10.62 



7.65 
13.00 



10.32 



2.10 

2.88 

2.49 



4.00 
6.20 



5.10 



0.00 
<x5.70 



2.85 



0.50 
.00 



.25 



a 36. 95 
a 48. 81 



42.88 



Fallbrook (57) ; elevation 700 feet. 

[Authority, U. S. "Weather Bureau.] 



1875-.76 














6.17 


3.78 


2.77 


0.15 


0.61 


0.00 




1876-77 






0.15 


0.00 


0.20 


0.23 


0.07 


0.08 


3.41 


.59 


2.28 


.55 


1.11 


.00 


8.67 


1877-78 






.00 


Tr. 


.00 


.59 


.58 


4.02 


3.19 


8.01 


2.08 


4.63 


1.41 


.33 


24.84 


1878-79 






.00 


Tr. 


.00 


.32 


.25 


1.64 


3.21 


.90 


.29 


.83 


.03 


.23 


7.70 


1879-80 






.00 


.05 


.00 


.42 


3.61 


5.87 


1.46 


1.86 


2.12 


4.99 


.05 


.02 


20.45 


1880-81 






.03 


.26 


.11 


.74 


1.27 


3.22 


3.51 


.73 


2.93 


.67 


.00 


.00 


13.47 


1881-82 






.00 


.00 


.00 


.57 


.24 


.35 


2.65 


4.02 


2.42 


1.64 


.09 


.26 


12.24 


1882-83 






Tr. 


.12 


.03 


.70 


1.01 


.33 


3. 46 


2.68 


1.89 


1.23 


1.87 


.00 


13.32 


1883-84 


, 




.00 


.00 


.00 


2.96 


.00 


3.32 


3.56 


15.36 


10.90 


3.13 


1.02 


.52 


40.77 


1884-85 






.00 


.02 


.20 


.53 


.54 


7.07 


.92 


.13 


.29 


2.60 


.29 


.11 


12.70 


1885-86 






.00 


.02 


.00 


.00 


5.92 


1.13 


9.76 


1.13 


4.70 


3.43 


.00 


.14 


26.23 


1886-87 






Tr. 


.11 


.12 


.04 


1.95 


.30 


.28 


5.65 


.05 


2.02 


.24 


.06 


10.82 


1887-88 






.05 


.00 


.83 


.20 


2.03 


3.56 


3.89 


2.55 


5.88 


.28 


.81 


.02 


20.10 


1888-89 






.03 


.00 


.00 


.80 


3.48 


6.13 


1.49 


2.35 


7.97 


.63 


.47 


.11 


23.46 


1889-90 






.00 


.07 


.05 


2.11 


.58 


15.53 


5.14 


2.22 


.80 


.09 


.30 


.02 


26.91 


1890-91 






.00 


.26 


.49 


.00 


.58 


3.22 


.40 


11.93 


.56 


1.35 


.89 


.00 


19.68 


1891-92 


.. 




.02 


.00 


.13 


.02 


.01 


2.64 


1.10 


4.59 


2.71 


.62 


1.46 


.19 


13.49 


1892-93 






.00 


.00 


.00 


.32 


2.85 


2.14 


3.40 


3.72 


8.06 


.49 


.29 


.00 


21.27 


1893-94 






.13 


.00 


.06 


.86 


1.46 


3.58 


.87 


1.10 


1.36 


.08 


.31 


.00 


9.81 


1894-95 


, 




.04 


.18 


.38 


.06 


.00 


6.09 


12.52 


1.59 


2.14 


.61 


.24 


.00 


23.85 


1895-96 






.00 


.00 


.00 


.06 


1.46 


.47 


3.45 


Tr. 


3.44 


.26 


.13 


.00 


9.27 


1896-97 


• • 




.05 


.05 


.00 


2.68 


1.22 


2.13 


4.20 


6.61 


4.37 


.06 


.21 


.00 


21.58 



115536 °— 19— wsp 446- 



a Estimated. 



-20 



306 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 

Table C4. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

Fallbrook (57) ; elevation, 700 feet— Continued. 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1897-98 


.01 


Tr. 


Tr. 


2.82 


.17 


.38 


2.65 


.71 


1.48 


.46 


2.23 


.07 


10.98 


1898-99 


Tr. 


Tr. 


Tr. 


.00 


.02 


1.04 


3.51 


.66 


2.23 


.16 


.18 


.90 


8.70 


1899-1900 


.00 


.03 


.00 


1.25 


2.90 


2.22 


3.26 


.29 


.76 


1.00 


1.76 


Tr. 


13.47 


1900-1901 


.00 


.00 


.06 


.23 


5.06 


.00 


4.24 


5.17 


.42 


.10 


1.26 


.06 


16.60 


1901-2 


.00 


.08 


Tr. 


.87 


.75 


Tr. 


2.84 


3.48 


3.52 


.75 


.11 


.05 


12.45 


1902-3 


.23 


.00 


.00 


.29 


2.86 


4.00 


3.11 


3.33 


5.19 


4.35 


.08 


.05 


23.49 


1903-4 


.00 
.03 


.00 
.05 


.15 
.10 


.11 
.73 


.05 
1.51 


.05 
2.98 


.48 
3.39 


2.94 
3.38 












27-year means 


2.99 


1.37 


.62 


.12 


17.27 



Divide between Santa Ysabel and Warners (58) ; elevation, 3,200 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1912-13 

1913-14 

1914-15 

3-year means 



a0.10 
.26 
.03 


a0. 70 
1.31 
.00 


aO.OO 
Tr. 
Tr. 


a3.00 

.32 

1.54 


«1.80 
3.51 
1.22 


oO.lO 
2.37 
5.35 


a3.00 
9.52 
13.17 


6.76 
6.53 
10.21 


3.06 
1.73 
1.10 


0.99 
3.36 
9.36 


0.54 

.00 

2.26 


0.48 
.82 
.08 


.13 


.67 


.00 


1.62 


2.18 


2.61 


8.56 


7.83 


1.96 


4.57 


.93 


.46 



K i n con or Warner's ranch (59) ; elevation, 2,975 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1912-13. 
1913-14. 
1914-15. 



3-year means . 



«0.20 
.26 
.53 


a0.40 
.90 
.00 


aO.OO 
.00 
Tr. 


a2.20 
.40 
.94 


a0.80 
2.74 
1.00 


oO.lO 
1.71 
4.91 


a3.00 
8.75 
11.69 


7.92 
8.24 
12.98 


2.09 
2.00 
1.69 


0.49 

1.98 
7.54 


0.18 

.00 

1.29 


0.32 
.22 

.14 


.33 


.43 


.00 


1.18 


1.51 


2.24 


7.81 


9.71 


1.93 


3.34 


.49 


.23 



La Mesa dam (60); elevation, 500 feet. 

[Authority, Cuyamaca Water Co., W. S. Post, engineer.] 



1912-13 

1913-14 

1914-15 

3-year means . 



<70.00 
.12 
.00 


a0.25 
.00 
.00 


aO.OO 
.00 
.00 


aO.60 
.00 
1.35 


a0.40 
2.99 
1.17 


aO.OO 
1.01 
2.67 


1.43 
4.13 
6.50 


2.61 
3.12 
5.14 


1.04 

.61 

1.24 


0.20 
1.34 
2.83 


0.30 

.30 

1.12 


0.09 
.19 
.00 


.04 


.08 


.00 


.65 


1.52 


1.23 


4.02 


3.62 


.96 


1.46 


.57 


.09 



Sutherland dam site (61); elevation, 1,900 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1913-14. 
1914-15. 



1913-14. 
1914-15. 



0.00 



0.00 



1.34 



l.: 



3.96 



8.48 
9.58 



5.54 

5.78 



1.54 
3.27 



.23 



0.70 
5.35 



0.45 
.00 



Santa Maria dam site (62); elevation, 1,400 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



0.00 0.00 



0.00 



1.09 



1.15 



4.01 



5.83 
8.76 



4.05 
5.85 



0.93 
2.10 



2.21 
2.65 



0.70 
2.81 



0.38 
0.00 



Pamo camp (63) ; elevation, 975 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 



1913 14 














4.50 
7.45 


4.33 
6.34 


1.14 
1.65 


1.37 
3.13 


0.53 
4.31 


0.24 

.00 




1914-15. 


0.00 


0.00 


0.02 


0.90 


1.65 


2.73 


28. 18 








a Estimated. 



DETAILED PRECIPITATION RECORDS. 



307 



Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

Carroll dam site (64) ; elevation, 250 feet. 

[Authority, Volcan Land & Water Co., W. S. Post, engineer.] 






Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan ; 


Feb. 


Mar. 


Apr. May. 


June. 


Total. 


1914-15 












12.77 


9.04 


10.29 


2.80 


6.44 


4.89 


0.00 



















Point Loma (65); elevation, 302 feet. 

[Authority, U. S. Weather Bureau.] 



1903-4 














0.05 
3.35 


2.27 

5.03 


2.26 
2.27 


0.24 

.55 


0.15 

.51 


0.01 
.02 




1904-5 


Tr. 


Tr. 


0.04 


0.18 


0.00 


1.51 


13.46 


1905-6 


0.15 


0.00 


.28 


.20 


3.31 


.21 


1.16 


1.92 


5.05 


.54 


.77 


.08 


13.67 


1906-7 


.04 


.10 


.21 


.05 


.74 


3.11 


3.09 


.52 


1.76 


.18 


.01 


.33 


10.14 


1907-8 


.10 


.00 


.00 


1.59 


.12 


.62 


3.05 


2.29 


.53 


.28 


.10 


Tr. 


8.68 


1908-9 


.04 


1.26 


.38 


.47 


1.03 


.42 


3.39 


1.93 


2.31 


.02 


.04 


.03 


11.32 


1909-10 


.01 


.00 


.07 


.02 


3.1o 


3.19 


2.92 


.21 


1.35 


.18 


.02 


Tr. 


11.13 


1910-11 


.03 
.10 


Tr. 
.06 


.08 
.25 


2.33 
.50 


.69 
.05 


.40 
1.04 


3.07 
.69 


4.56 
.16 


1.19 

4.67 


.45 
2.37 


.01 
.16 


.03 
.22 


12.84 


1911-12 


10.27 


1912-13 


.17 


.41 


.01 


.43 


.47 


.06 


1.19 


2.24 


.42 


.13 


.18 


.16 


5.87 


1913-14 


.05 


.02 


.03 


.04 


2.02 


.87 


4.76 


2.22 


.76 


.80 


.15 


.14 


11.86 


1914-15 


.00 


.00 


.02 


.90 


.77 


2.34 


5.53 


3.86 


.49 


1.73 


.42 


Tr. - 


16.06 


11-year means 


.06 


.17 


.13 


.61 


1.12 


1.25 


2.93 


2.26 


1.89 


.66 


.22 


.09 


11.39 



Otay (66); elevation, 90 feet. 

[Authority, George G. Downes. Gage has good exposure.] 



1908-9 


0.00 


0.00 


0.00 


0.43 


1.08 


0.39 


2.72 


2.31 


4.64 


0.09 


0.00 


0.00 


11.66 


1909-10 


.00 


.00 


.02 
TrA 


3.79 


5.40 


2.54 


.50 


1.44 


.49 


.00 


.00 


.00 


14.18 


1910-11 


.00 


.00 


1.51 


.70 


.37 


2.76 


3.10 


.66 


.44 


.00 


.00 


9.54 


1911-12 


.07 


.00 


.22 


.23 


.19 


1.20 


.49 


.00 


5.17 


1.93 


.12 


.19 


9.81 


1912-13 


.20 


.28 


.00 


.43 


.56 


.00 


1.50 


2.64 


.48 


.14 


.10 


.12 


6.45 


1913-14 


.04 


.00 


.00 


.00 


1.96 


.92 


3.47 


2.07 


.70 


.36 


,18 


.00 


9.70 


1914-15 


.00 


.00 


.07 


1.76 


1.22 


2.33 


5.24 


3.11 


.68 


1.32 


.45 


.00 


16.18 


7-year means 


.04 


.04 


.04 


1.16 


1.59 


1.11 


2.38 


2.09 


1.83 


.61 


.12 


.05 


11.07 



Lower Otay reservoir (67) ; elevation 486 feet. 

[Authorities: 1905 to 1914, Southern California Mountain Water Co.; 1914-15, city of San Diego.] 



1905-6 














0.74 


5.39 


3.12 


2.75 


0.72 


0.00 




1906-7 


0.00 


0.08 


0.00 


0.02 


1.31 


3.31 


4.54 


.74 


2.85 


*.35 


.09 


.22 


13.51 


1907-8 


.00 


.00 


.00 


.78 


.00 


.35 


4.35 


2.52 


2.00 


.73 


.05 


.00 


10.78 


1908-9 


.00 


1.20 


.14 


.35 


.80 


.00 


3.94 


2.39 


2.20 


.00 


.00 


.00 


11.02 


1909-10 


.00 


.00 


.00 


.00 


1.50 


4.74 


1.85 


.05 


1.56 


.52 


.00 


.00 


10.22 


1910-11 


.00 


.00 


.00 


1.34 


1.39 


.33 


3.13 


3.59 


1.21 


.64 


.00 


.00 


11.63 


1911-12 


.03 


.00 


.16 


.24 


.06 


1.19 


.79 


.00 


7.29 


2.49 


1.13 


.29 


13.67 


1912-13 


.01 


.20 


.00 


1.26 


1.97 


.16 


1.51 


3.89 


.67 


.15 


.04 


.23 


10.09 


1913-14 


.10 


.05 


.00 


.01 


2.17 


1.63 


2.98 


2.17 


.85 


.78 


.15 


.00 


10.89 


1914-15 


.00 


.00 


.00 


.80 


.63 


2.58 


2.77 


3.97 


.87 


1.79 


1.00 


.00 


14.41 


9-year means 


.02 


.17 


.03 


.53 


1.09 


1.58 


2.87 


2.15 


2.16 


.83 


.27 


.08 


11.80 



Los Padres ranch (68) ; elevation, 490 feet. 

[Authorities: 1901 to 1910-11, U. S. Weather Bureau; 1912 to 1914-15, M. G. Allen.] 



1901-2 


0.00 


0.00 


0.20 


0.30 


0.50 


0.40 


3.10 


2.60 


3.30 


0.30 


0.00 


0.00 


10.70 


1902-3 


.70 


.00 


.00 


.90 


1.25 


2.40 


.75 


3.50 


1.05 


1.50 


.00 


.00 


12.05 


1903-4 


.00 


.00 


.30 


.00 


.35 


2.50 


.10 


2.33 


3.22 


.25 


.23 


.00 


9.28 


190^5 


.00 


.00 


.40 


.00 


.00 


2.85 


3.27 


9.62 


5.05 


.58 


.66 


.00 


22.43 


1905-6 


.00 


.00 


.20 


.45 


4.85 


.70 


1.32 


2.93 


7.73 


2.16 


1.17 


.00 


21.51 


1906-7 


.00 


.00 


.35 


.00 


2.26 


5.27 


5.12 


1.50 


3.73 


.39 


.30 


.00 


18.92 


1907-8 


.00 


.46 


.00 


1.57 


.87 


.00 


5.05 


3.71 


1.77 


1.09 


.98 


.00 


15.50 


1908-9 


.00 


1.28 


.49 


.76 


.82 


1.82 


5.55 


3.58 


5.55 


.00 


.00 


.00 


19.85 


1909-10 


.00 


.00 


.36 


.00 


3.49 


5.02 


3.63 


.57 


2.57 


.33 


.00 


.00 


15.97 


1910-11 


.00 


.00 


.34 


.81 


1.46 


.60 


4.02 


5.05 


1.39 


1.02 


1.02 


.00 


15.71 


1912-13 


.00 


.00 


.70 


.00 


.70 


.00 


1.60 


4.02 


1.00 


.00 


.00 


.00 


8.02 


1913-14 


.00 


.00 


.00 


.00 


2.50 


1.06 


4.70 


3.97 


.70 


1.05 


.17 


.00 


14.15 


1914-15 


.00 


.00 


.00 


1.06 


1.42 


2.76 


6.05 


5.66 


1.08 


1.94 


2.30 


.00 


22.27 


13-year means 


.05 


.13 


.26 


.45 


1.57 


1.95 


3.40 


3.76 


2.93 


.82 


.53 


.00 


15.87 



308 GKOUND WATEKS OF WESTEKN SAN DIEGO COUNTY, CALIF. 

Table 64. — Monthly and annual -precipitation at 106 stations in or near San Diego 

County — Continued . 

Bonita (69); elevation, 110 feet. 

Authorities: 1899 to 1913-14, G. A. Norton; 1914-15, R. M. Allen and U. S. Weather Bureau. Mr. 
Norton let water of each storm accumulate until end of storm; used redwood stick but was very careful 
to read quickly and so eliminated crawl. Record kept at residence of R. C. Allen, of the Sweetwater 
Fruit Co. Rain gage is U. S. Weather Bureau standard.] 



July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


0.00 


0.00 


0.00 


0.36 


1.21 


0.79 


0.45 


0.05 


0.47 


0.99 


1.45 


0.00 


.00 


.00 


.00 


.28 


1.36 


.00 


1.53 


3.65 


.44 


Tr. 


.74 


.00 


.00 


.00 


.00 


.37 


.00 


.11 


1.94 


1.37 


2.61 


.32 


Tr. 


Tr. 


1.15 


.00 


.00 


.04 


1.30 


2.97 


.91 


2.28 


1.17 


1.12 


.00 


.00 


.00 


.00 


.00 


.14 


.00 


.12 


.12 


1.98 


2.05 


.21 


.27 


.00 


.00 


.00 


.00 


.26 


.00 


2.16 


1.80 


6.64 


2.93 


.26 


.92 


.00 


.00 


.00 


.69 


.30 


4.12 


.58 


1.12 


2.32 


5.69 


1.77 


.79 


.07 


.00 


.00 


.00 


.00 


1.39 


4.20 


4.12 


.97 


2.01 


.16 


.00 


.00 


.00 


.00 


.00 


1.79 


.00 


.37 


3.50 


2.96 


1.14 


.42 


.16 


.00 


.00 


.72 


.08 


.20 


1.00 


.56 


3.73 


2.21 


3.65 


.00 


.00 


.00 


.00 


.00 


.00 


.00 


2.66 


3.69 


2.19 


.38 


1.22 


.46 


.00 


.00 


.00 


.00 


.00 


.87 


.84 


.20 


2.97 


3.47 


.76 


.50 


.00 


.00 


.00 


.00 


.25 


.64 


.00 


1.61 


.81 


.00 


5.17 


2.28 


.96 


.32 


.00 


.15 


.00 


.75 


.38 


.00 


1.88 


2.78 


.64 


.17 


.00 


.12 


.00 


.00 


.00 


Tr. 


2.06 


.75 


4.30 


2.21 


.78 


.77 


.08 


.00 


.00 


.00 


.08 


1.06 


.81 


2.24 


4.64 


3.32 


.95 


1.73 


.71 


.00 


.07 


.05 


.07 


.44 


1.07 


1.27 


2.25 


2.29 


1.98 


.70 


.38 


.03 



Total. 



1899-1900 

1900-1901 

1901-2 

1902-3 

1903-4 

1904-5 

1905-6 

1906-7 

1907-8 

1908-9 

1909-10 

1910-11 

1911-12 

1912-13 

1913-14 

1914-15 

16-vcar means. 



5.77 
8.00 
6.72 
10.94 
4.89 
14.97 
17.45 
12.85 
10.34 
12.15 
10.60 
9.61 
12.04 
6.87 
10.95 
15.54 



Rockwood ranch (70) ; elevation, 430 feet. 

[Authority, L. D. Rockwood. Exposure of gage is good. It is on slope 250 feet northeast of house and 
250 feet northwest of barn. Measurements taken with stick graduated in inches and hundredths. 
Readings made daily since October, 1901. Prior to this, weekly or for storms, readings being made 
oftcner during big storms.] 



1893-94 


0.00 


0.00 


0.00 


0.62 


0.62 


2.50 


0.75 


0.62 


1.00 


0.00 


0.00 


0.00 


6.11 


1894-95 


.00 


.00 


.00 


.00 


.00 


3.88 


10.25 


1.00 


.12 


.00 


.00 


.00 


15.25 


1895-96 


.00 


.00 


.00 


.00 


2.00 


.50 


3.25 


.00 


4.50 


.00 


.00 


.00 


10.25 


1896-97 


.00 


.00 


.00 


1.25 


.75 


2.00 


3.75 


4.50 


2.00 


.00 


.00 


.00 


14.25 


1897-98 


.00 


.00 


.00 


.62 


.00 


.00 


1.75 


.25 


1.75 


.00 


1.00 


.00 


6.37 


1898-99 


.00 


.00 


.00 


.50 


.00 


1.00 


2.25 


1.00 


2.12 


.00 


.00 


.00 


6.87 


1899-1900 


.00 


.00 


.00 


.95 


1.68 


1.24 


5.25 


.00 


.41 


1.16 


1.05 


.00 


11.74 


1900-1901 


.00 


.00 


.00 


.15 


3.05 


.00 


1.62 


5.22 


.00 


.00 


1.90 


.00 


11.94 


1901-2 


.00 


.00 


.00 


.20 


.40 


.00 


1.99 


o2.64 


4.02 


.50 


.00 


.00 


9.75 


1902-3 


.00 


.00 


.00 


.25 


2.27 


1.89 


.82 


3.43 


2.79 


3.53 


.00 


.00 


14.98 


1903^1 


.00 


.00 


.00 


.00 


.00 


.00 


.10 


1.28 


3.18 


.55 


.21 


.00 


5.32 


1904-5 


.00 


.00 


.00 


.50 


.00 


1.58 


3.05 


6.60 


6.45 


.86 


.90 


.00 


19.94 


1905-6 


.00 


.00 


.00 


.00 


2.18 


.40 


2.14 


2.42 


8.27 


1.60 


1.09 


.00 


18.10 


1906-7 


.00 


.00 


.00 


.00 


1.26 


4.38 


4.77 


1.30 


3.17 


.25 


.00 


.00 


15.13 


1907-8 


.00 


.00 


.00 


2.33 


.62 


.63 


2.92 


3.46 


1.18 


.75 


.22 


.00 


12.11 


1908-9 


.00 


1.50 


.00 


.00 


.60 


.78 


6.12 


3.72 


2.00 


.00 


.00 


.00 


14.72 


1909-10 


.00 


1.50 


.00 


.00 


3.45 


6.88 


.90 


.30 


1.46 


.00 


.00 


.00 


14.40 


1910-11 


.00 


.00 


.00 


.97 


1.41 


.33 


4.55 


4.88 


1.83 


.71 


.00 


.00 


14.68 


1911-12 


.00 


.00 


.30 


.30 


.33 


1.67 


.85 


.00 


7.56 


3.25 


1.28 


.00 


15.54 


1912-13 


.00 


.78 


.00 


1.16 


.00 


.28 


1.75 


3.71 


1.11 


.67 


.00 


.00 


9.46 


1913-14 


.00 


.00 


.00 


.00 


2.29 


1.12 


5.57 


3.63 


1.26 


1.43 


.00 


.00 


15. 30 


1914-15 


.00 


.00 


.00 


1.20 


1.16 


2.52 


6.92 


5.19 


1.21 


4.37 


2.12 


.00 


24.69 


22-year means 


.00 


.17 


.01 


.55 


1.10 


1.53 


3.24 


2.51 


2.61 


.90 


.44 


.00 


13.04 



Boulder Creek (71) ; elevation, 2,990 feet. 

[Authoiity, Volcan Land & Water Co., W. S. Post, engineer.] 



1914-15. 



12.77 9.04 10.29 2.80 6.44 4.89 0.00 



Harvey ranch (72); elevation, 514 feet. 

[Authority, A. M. Logan.] 



1913-14 














3.77 
4.51 


2.74 
3.66 


0.72 
.94 


0.98 


0.15 


0.00 




1914-15 


0.00 


0.00 


0.03 


0.84 


1.00 


2.21 















o Storm of Feb. 2 not included. 



DETAILED PRECIPITATION RECORDS. 309 

Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

Jamul ranch (73); elevation, 800 feet. 

[Authority, Thos. Popplewell.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1911-12 














0.60 
a3.00 
4.89 
6.66 

4.83 


0.00 

4.96 
3.54 
4.18 

4.57 


10.34 

1.44 

.90 

2.48 

1.96 


2.83 

.19 

1.15 

2.68 

1.44 


1.15 
.18 
.20 

1.90 

1.04 


0.00 

.00 
.00 
.00 

.00 




1912-13 


0.00 


00 


0.00 


0.90 


0.80 

2.33 

.92 

.81 


0.00 
1.22 
2.37 

1.19 


all. 47 


1913-14 




1914-15 


.00 
.00 


.00 
.00 


.00 
.00 


.87 
.88 


22.06 


2-year means 


16.77 



Dulzura (74); elevation, 1,075 feet. 

[Authority, Clark Bros.] 



1913-14. 
1914-15. 



0.00 



0.00 



0.00 1.35 



1.64 


1.13 


5.41 


4.47 


0.83 


1.67 


0.00 


0.00 


.90 


2.22 


7.65 


5.68 


2.02 


3.33 


.88 


.00 



24.03 



Marron Valley (75) ; elevation, 575 feet. 

[Authority, Donohoe Bros.] 



1913-14 










1.73 


4.26 
5.51 


3.20 
3.42 


0.56 
.53 


1.51 
3.04 


0.22 
1.41 


0.00 
.00 




1914-15 


0.00 


0.00 


0.00 


.82 


.64 2.82 


18.19 







Winetka Valley (76); elevation, 2,500 feet. 

[Authority, L. Harvey.] 



1913-14 












6.73 

7.86 


5.00 

7.40 


1.35 
2.52 


2.06 
4.71 


0.25 


0.00 




1914-15 


0.00 


000 


0.00 


1.60 


1.17 


3.09 













Lyon Peak (77) ; elevation, 3,755 feet. 

[Authority, R. Wueste.] 



1913-14 ...J 










2.22 
6.00 


0.34 
2.51 


0.27 
.00 




1914-15 


0.00 


6.66 o.io 


1.58 


1.61 


3.55 


6.35 


7.00 


1.32 


30.02 



Lyon Valley (78) ; elevation, 2,200 feet. 

[Authority, R. Wueste.] 



1913-14 




















2.27 
6.13 


0.20 
3.49 


0.25 
.00 




1914-15 


0.00 


6.66 


0.10 


1.33 


1.45 


4.34 


7.95 


9.14 


2.66 


36.59 





The Willows (79); elevation, 2,300 feet. 

[Authority, F. B. Walker.] 



1913-14 


















0.97 

.84 


2.09 


0.16 


0.21 




1914-15 


0.00 


0.00 


0.06 


1.33 


1.16 


3.43 


7.06 


8.09 















Cottonwood (80); elevation, 875 feet. 

[Authority, L. W. Smith.] 



1913-14 














4.02 


0.67 
1.84 


1.29 
1.98 


0.31 
2.65 


0.00 
.00 




1914-15 


0.17 


0.00 


0.00 


0.60 


0.79 


3.29 


6.28 5.05 


22.65 





310 GROUND WATERS OF WESTERN SAN DIEGO COUNTY, CALIF. 



Table 64.^- Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 



1912-13. 
1913-14. 
1914-15 . 



2-year means . 



Tecate (81); elevation, 1,775 feet. 

[Authority, G. F. Robinson.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1913-14 














5.72 
6.41 


3.81 
5.04 


0.66 
1.50 


2.05 
2.62 


0.57 

2.74 


0.00 
.00 




1914-15 


0.00 


0.00 


0.37 


0.63 


0.62 


3.80 


23.73 







Petrero (82) ; elevation, 2,390 feet. 

[Authority, G. Nelson.] 



1913-14 




1 






7.12 
7.23 


4.75 
6.65. 


0.96 
2.05 


1.93 
2.68 


0.34 
3.03 


0.11 

.00 




1914-15 


0.00 


6.66 6. is 6.87 


0.90 


3.78 


27.34 






Skye Valley (83) ; elevation, 2,550 feet. 

[Authority, G. F. Korte.] 


1912-13 
















3.33 
4.92 
6.16 


1.55 
1.05 
1.80 


"i.'69* 
5.55 


0.21 

.21 


0.10 

.00 




1913-14 


1.00 
.10 


0.40 
.00 


1.10 

.08 


0.06 
.85 


1.95 
1.26 


1.35 
3.33 


5.72 
5.04 


19.45 


1914-15 














Grigsby's ranch (84) ; elevation, 2,690 feet. 

[Authority, A. B. Grigsby.] 

















5.50 
4.35 
6.15 


2.32 
1.02 
2.16 


0.40 
2.23 
2.28 


0.00 

.64 

3.28 


0.24 
.00 
.00 


35 
1.32 


2.42 
.00 


al.50 
.05 


a0.33 
.81 


2.20 

.86 


1.38 
4.36 


5.71 
7.31 


.84 


1.21 


.77 


.57 


1.53 


2.92 


6.51 


5.25 


1.59 


2.26 


1.96 


.00 



El Cajon (city) (85); elevation, 482 feet. 

[Authority, T. J. Cox.] 



1881-82 














0.83 
1.89 

.54 
7.29 

.00 
3.62 
1.54 
2.38 

.60 
1.34 
1.26 

.59 
11.32 


1.71 
9.66 

.58 
2.90 
4.47 
1.30 
2.40 
2.89 
6.14 
3.19 
1.39 

.84 
1.06 


1.07 
7.06 

.75 
2.11 

.16 
4.17 
4.44 

.68 

.89 
2.04 
7.94 
1.79 
1.62 


1.10 

3.58 

1.88 

2.26 

1.97 

.36 

.33 

.05 

1.35 

.25 

.32 

.00 

.17 


1.04 

2.65 

.28 

.00 

.13 

.00 

.28 

.21 

1.01 

1.89 

.08 

.22 

.18 


0.00 
.40 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.15 
.00 




1882-83 


0.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.00 
.CO 
.00 

.00 


0.00 
.00 
.00 
.00 
.00 

-.00 
.00 
.18 
.00 
.00 
.00 
.00 
.00 

.02 


0.09 
.00 
.00 
.00 
.00 
.00 
.35 
.00 
.91 
.00 
.00 
.00 
.00 

.11 


0.20 
1.67 
.24 
.08 
.13 
.00 
.65 
3.77 
.03 
.00 
.35 
.31 
.00 

.62 


0.49 

:io 

.13 

1.67 

1.91 

2.33 

2.16 

.18 

.80 

.11 

1.02 

.97 

.00 

.99 


0.29 
2 64 
6.48 
.47 
.20 
3.07 
4.16 
8.54 
2.56 
2.05 
1.10 
2.12 
3.16 

2.81 


26.31 


1883-84 


8.44 


1884-85 


21.41 


1885-86 


8.95 


1886-87 


U.69 


1887-88 


14.39 


1888-89 

1889-90 


13.53 

22.66 


1890-91 


13.01 


1891-92 


13.15 


1892-93 


6 08 


1S93-94 


17.75 


1894-95 




12-year means 


2.70 


3.07 


2.80 


1.04 


.58 


.05 


14.78 



Buckman Springs (86) ; elevation, 3,400 feet. 

[Authority, W. O. Wolin.] 



1912-13. 
1913-14 . 
1914-15. 











0.53 
"".'68' 


0.46 
1.51 
5.06 


2.94 


5.59 


0.96 
1.05 
1.67 


0.13 
1.73 
2.53 


0.07 

.22 

2.93 


0.06 
.03 
.00 


0.34 
.70 


1.45 
.00 


0-17 
.68 


0.14 
.91 


8.76 


6.55 



Descanso Valley (87) ; elevation, 3,500 feet. 

[Authority, G. O. Brenner.] 



1913-14 




















1.09 
5.52 


0.33 
5-33 


0.29 
.00 




1914-15 . 


0.82 


0.00 


0.11 


1.56 


075 


4.82 


9.03 


9.83 


2.54 


40.31 







a Estimated. 



DETAILED PRECIPITATION RECORDS. 311 

\Table 64. — Monthly and annual 'precipitation at 106 stations in or near San Diego 

County — Continued . 

Laguna ranger station (88) ; elevation, 5,475 feet. 

[Authority, Leo Morris.] 



Total. 



1914-15. 



July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 














12.52 


5.84 


0.36 


8.27 


0.45 


0.00 















Bonita (89) ; elevation, 60 feet. 

[Authority, J. M. Voneida.] 



1913-14 








1 ' 




3.28 
4.37 


1.88 
2.62 


0.68 
.95 


0.75 
1.32 


0.11 
.67 


0.01 
.01 




1914-15 


0.00 


6.66 


0.10 


6.80 6.78 


2.35 


13.97 







Chollas Heights (90) ; elevation, 350 feet. 

[Authority, F. William Blatchford.] 



1913-14 














3.48 
5.44 


2.51 
4.71 


0.61 

.74 


1.05 
1.74 


0.04 
.86 


0.16 
.01 




1914-15 


0.00 


0.00 


0.00 


1.47 


1.11 


3.22 


i9.30 







Campbell's ranch (91); elevation, 2,575 feet. 

[Authority, Arch. Campbell.] 



1913-14 




1 












0.74 
1.72 


1.79 0.64 


0.00 


1914-15 


0.75 


6.66 6.75 


0.37 


0.60 


3.88 


6.36 


4.26 






1 


1 



Kitchen Valley (92) ; elevation, 5,250 feet. 

[Authority, Seth Swenson.] 



1914-15. 



12.02 



8.80 



1.00 



8.05 



0.66 0.00 



Dehesa (93) ; elevation, 580 feet. 

[Authority, J. H. Whitaker.] 



1913-14 




















2.05 
1.97 


0.14 
5.36 


0.17 
.00 




1914-15 


0.00 


0.00 


0.09 


0.98 


1.69 


2.66 


5.84 


5.62 


1.33 


25.59 







La Presa (94) ; elevation, 300 feet. 

[Authority, J. S. Dressier.] 



1914-15. 



0.00 0.00 0.00 1.01 0.88 2.67 5.11 3.73 0.78 



2.02 



0.93 0.00 17.13 



Nobles mine (96) ; elevation, 4,200 feet. 

[Authority, Thos. Noble, jr.] 



1912-13 














3.70 
5.73 


5.60 1.95 
4.15 1.31 


0.60 
2.28 


0.30 
.30 


0.17 
.15 




1913-14 


0.45 
.45 


0.74 
.30 


0.33 

.68 


0.21 
.97 


2.29 
.98 


1.60 


19.54 


1914-15 










1 


1 







312 GROUND WATERS OE WESTERN SAN DIEGO COUNTY, CALIF. 

Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

Japatul (97) ; elevation, 2,725 feet. 

[Authority, R. J. Grouse.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1913-14 


















1.17 
3.24 


0.54 
3.14 


0.17 
.00 




1914-15 


0.16 


0.00 


0.11 0.7ft 


1.08 


3.95 


8.06 


6.33 


2.02 


28.88 











Pueblo farm (98) ; elevation, 400 feet. 

[Authority, Max Watson.] 



1913-14 








1 


3.80 
6.05 


0.20 




0.00 




1914-15. 


0.00 


0.00 








2.50 . . 








| 1 











Modigajuat (99); elevation, 3,150 feet. 

[Authority, Charles Hook.] 



1914-15. 



0.00 


0.00 


0.00 


0.87 


0.63 


4.17 


7.84 


5.93 


2.40 


3.09 


3.45 


0.00 



28.38 



Rattlesnake Valley (100); elevation, 4,775 feet. 

[Authority, J. D. Harper.] 



1914-15. 



3.32 



8.41 



5.79 



3.09 



0.19 



La Posta (101); elevation, 3,300 feet. 

[Authority, R. S. Benton.] 



1914-15. 



7.75 



5.06 



2.03 



2.37 



2.78 



Viejas (102). 
[Authority, City of San Diego.] 



1914-15. 



8.09 



0.84 



4.01 



2.93 



Miramar (103); elevation, 660 feet. 

[Authority, G. A. Riley.] 



1901-2 


0.00 


0.00 


0.00 


0.45 


0.60 


0.00 


1.85 


1.45 


3.20 


0.60 


0.20 


0.00 


8.35 


1902-3 




.00 


.00 


.00 


.45 


3.05 


2.85 


1.30 


3.20 


1.60 


1.30 


.00 


.00 


13.75 


1903-4 




.00 


.00 


.00 


.20 


.00 


.15 


.30 


2.50 


3.13 


.25 


.25 


.00 


6.78 


1904-5 




.80 


.00 


.00 


.30 


.00 


2.45 


3.55 


6.95 


2.60 


.45 


.90 


.00 


18.00 


1905-6 




.00 


.00 


.20 


.15 


4.40 


.65 


1.80 


3.35 


7.45 


.95 


1.10 


.10 


20.15 


1906-7 




.00 


.00 


.25 


.00 


1.05 


5.25 


3.85 


.80 


2.35 


.10 


.30 


.28 


14.23 


1907-8 




.00 


.00 


.00 


.20 


1.65 


.55 


3. 60 


2.70 


1.00 


.50 


.25 


.00 


10.45 


1908-9 




.00 


.50 


.35 


35 


1.05 


.75 


4.67 


3.17 


2.32 


.00 


.30 


.00 


13.46 


1909-10 




.00 


.00 


.00 


.00 


3.45 


5.90 


3.50 


.45 


2.05 


.30 


.00 


.00 


15.65 


1910-11 




1.00 


.00 


.00 


1.10 


.85 


.30 


4.45 


5.10 


1.65 


1.20 


.00 


.17 


15.82 


1911-12 




.00 


.00 


.10 


.22 


.00 


1.50 


.97 


.00 


5.90 


3.15 


1.20 


.20 


13.24 


1912-13 




.00 


.45 


.00 


1.15 


.55 


.05 


1.50 


3.45 


1.15 


.40 


.30 


.05 


9.05 


1913-14 




.05 


.00 


.15 


.00 


2.15 


1.20 


5.35 


3.45 


1.00 


1.05 


.30 


.35 


15.05 


1914-15 




.00 


.00 


.00 


1.25 


1.55 


3.60 


8.95 


5.15 


1.10 


1.04 


1.50 


.00 


24.14 


14-year means 


.13 


.07 


.08 


.42 


1.45 


1.80 


3.16 


2.98 


2.61 


.81 


.47 


.08 


14.15 






DETAILED PRECIPITATION RECORDS. 



313 



Table 64. — Monthly and annual precipitation at 106 stations in or near San Diego 

County — Continued . 

Santa Fe ranch (104); elevation, 55 feet. 

[Authority, M. H. Crawford.] 



Season. 


July. 


Aug. 


Sept. 


Oct. 


Nov. 


Dec. 


Jan. 


Feb. 


Mar. 


Apr. 


May. 


June. 


Total. 


1911-12 


aO.OO 
.15 
.00 
.00 

.04 


oO.OO 
.00 
.00 
.00 

.00 


oO.lO 
.00 
.00 
.00 

.03 


a0.12 
.00 
.00 
.40 

.13 


oO.OO 

.90 

1.80 

1.13 

.96 


a0.75 

.00 

.60 

1.80 

.79 


0.00 
1.50 
4.19 
5.27 

2.74 


0.00 
2.17 
3.48 
4.52 

2.79 


5.39 

.56 
.00 
1.27 

1.81 


2.81 
.00 
.48 

1.77 

1.27 


1.10 
.00 
.00 
.19 

.32 


0.00 
.00 
.00 
.00 

.00 


ol0. 27 


1912-13 


5.28 


1913-14 


10.55 


1914-15 


16.35 


4-year means 


10.61 



Scripps Biological Institute (105); elevation, 50 feet. 

[Authority, G. F. McEwen.] 



1914-15. 



5.95 1.05 1.65 1.42 1.20 Tr 



Lauterbaughs (106). 

[Authority, city of San Diego.] 



1914-15. 



0.03 0.00 0.04 0.46 0.66 3. 



11 2.37 2.21 3.11 0.00 25.64 



Idyllwild, Riverside County. 

[Authority, IT. S. Weather Bureau.] 



1901 














3.47 
2.42 
3.82 
.80 
6.85 
3.34 
7.30 
3.96 
12.16 
5.20 
9.35 


5.81 
5.25 
3.00 
2.70 
8.43 
5.32 
2.71 
3.85 
7.27 
.60 
6.26 


1.23 
5.53 
6.76 
4.59 
10.07 
16.15 
6.78 
1.67 
4.56 
3.08 
6.03 
12.77 

6.52 


0.37 

.09 

6.10 

2.19 

2.21 

3.19 

.89 

2.34 

.26 

.33 

1.34 

3.01 

.1.89 


1.22 

.20 

.48 

1.42 

3.77 

2.73 

1.48 

1.14 

.15 

.00 

.00 

1.56 

1.14 


0.00 
.10 
.09 
.00 
.00 
.04 
.43 
.00 
.00 
.00 
Tr. 




1901-2 


0.34 
.33 
.00 
Tr. 
.03 
.73 
.05 

1.50 

1.00 
.55 

1.02 

.45 


3.44 
.00 
.57 

2.45 
.17 

2.77 
.00 

2.73 

1.87 
.21 
.00 

1.42 


0.00 
Tr. 

2.21 
Tr. 
.38 
.14 
Tr. 

3.11 

.40 

15 

.80 

.64 


1.03 
.10 
.47 
.25 
Tr. 
.03 

4.55 

1.85 
.00 

1.43 
.43 

.97 


0.69 
3.80 

.00 

.00 
8.38 
2.15 
1.11 

.70 
4.34 
2.40 

.15 

2.36 


0.34 

2.00 

.00 

.98 

1.93 

5.25 

2.64 

1.05 

8.53 

.10 

2.10 

2.28 


19. 13 


1902-3 


26.48 


1903-4 


14.95 


1904-5 


35.01 


1905-6 


41.66 


1906-7 


30. 66 


1907-8 


21.31 


1908-9 


35.34 


1909-10 


25.35 


1910-11 


27.82 


1911-12 




10-year means 


5.52 


4.54 


.07 


27.80 



San Jacinto, Riverside County; elevation, 1,550 feet. 

[Authority, U. S. Weather Bureau.] 



1893-94 

1894-95 

1895-96 

1896-97 

1897-98 

1898-99 

1899-1900 

1900-1901 

1901-2 

1902-3 

1903-4 

1904-5 

1905-6 

1906-7 

1907-8 

1908-9 

1909-10 

1910-11 

1911-12 

1912-13 

1913-14 

1914-15 

22-year means 



0.03 


0.00 


0.51 


0.C6 


0.80 


3.16 


0.67 


0.96 


0.89 


0.10 


1.15 


0.00 


.13 


.03 


.04 


.04 


.00 


5.30 


7.81 


1.53 


.99 


.51 


.26 


.03 


Tr. 


Tr. 


.00 


Tr. 


2.09 


.34 


2.04 


.10 


3.70 


.71 


.22 


.00 


.07 


Tr. 


.40 


1.76 


1.20 


1.70 


3.55 


3.74 


2.24 


a. 71 


.14 


a. 00 


a. 08 


a. 10 


.16 


3.38 


.34 


.47 


2.25 


.49 


.81 


a. 71 


a. 67 


a. 00 


.22 


.54 


.00 


.00 


.18 


1.38 


2. 38 


.69 


1.63 


a. 71 


a. 67 


a. 00 


a. 08 


a. 10 


.00 


.81 


1.83 


.75 


1.42 


.00 


.76 


1.97 


1.86 


.00 


.01 


.00 


.01 


.42 


4.57 


.00 


2.86 


4.62 


.33 


.03 


.55 


.00 


.00 


1.53 


.06 


.61 


.06 


Tr. 


1.55 


1.57 


2.31 


.53 


0.1 


.01 


.10 


.00 


.00 


.06 


1.25 


2.12 


1.32 


1.37 


4.54 


4.99 


.00 


Tr. 


.00 


.11 


1.16 


.00 


.00 


al.64 


.32 


ol.l5 


3.02 


.35 


.15 


.00 


.00 


.32 


.00 


.13 


.00 


1.02 


3.46 


6.48 


4.89 


1.03 


1.26 


.00 


.00 


.37 


.00 


.24 


2.54 


.22 


1.42 


1.99 


6.50 


.94 


.57 


.00 


.52 


Tr. 


.12 


.00 


2.43 


4.79 


5.11 


2.03 


2.98 


.04 


.00 


.00 


.00 


.00 


.00 


3.30 


.11 


.57 


3.81 


2.92 


1.61 


.35 


.00 


.00 


.17 


.45 


.45 


.91 


.20 


.58 


3.96 


3.25 


3.64 


.00 


.15 


.00 


.18 


.23 


.00 


.00 


1.70 


4.89 


2.99 


.24 


2.29 


.00 


.00 


.00 


.00 


.00 


.00 


.90 


2.94 


.00 


4.71 


3.19 


2.31 


1.39 


.00 


.00 


.00 


.00 


.50 


.28 


.00 


.00 


.15 


.00 


7.29 


3.24 


1.18 


.00 


.00 


.50 


.00 


1.33 


.48 


.00 


1.07 


3.50 


.97 


.61 


.00 


.16 


.20 


.40 


.00 


.00 


2.13 


1.34 


5.55 


3.84 


1.03 


4.07 


.06 


.25 


.00 


.00 


.00 


.08 


.55 


2.59 


4.65 


7.05 


.21 


2.13 


.00 


.00 


.08 


.22 


.16 


.68 


1.15 


1.49 


2.87 


2.31 


2.50 


1.14 


.40 


.02 



a Estimated. 



INDEX. 



Page. 
Absorption of water from stream flow, rate 

and amount of 144-145 

Acids , effects of, in water used in manufacture 247 

Acknowledgments for aid 19-20 

Acre-foot, equivalent of 287 

Aguanga, precipitation at 295 

Alfalfa, duty of water for 193 

Alkali, accumulation of, from applied water . . 233 

endurable proportion of 230-232 

limit of toleration of, by plants 233-236 

removal of 236-238 

source and occurrence of 229-230 

Alkalies, common, relative harmfulness of. 232-236 
Analyses and assays of waters from wells and 

springs 260-263 

methods used in 222-223 

Angelus Heights, well at, description of 179 

well at, log of 63 

Area covered by the survey 18 

Areas, grouping of, with regard to ground 

water 105-106 

B. 

Balboa oil well, log of. 55-56 

Barrett dam, precipitation at 305 

Basins, highland, general features of 41-43 

highland, origin of 46, 48-50 

Batiquintos Lagoon, deep well on 180 

well near 170 

Beach deposits, late Tertiary, nature of 68 

Bear Valley, description of 46-47 

Beaver oil well, log of 68 

Bentley, Charles, test of pumping plant of. 273-274 

well of 202 

Bibliography 288-290 

Boiler use, water for, improvement of 241-242 

water for, injurious substances in 239-241 

numerical rating of 243-246 

Bonita (station 69), precipitation at 308 

Bonita (station 89), precipitation at 311 

Boulder Creek, precipitation at 308 

Buckman Springs (station 49), precipitation 

at 304 

Buckman Springs (station 86), precipitation 

at 310 

Buena Vista Creek, well near 169-170 

C. 
Calcium, effects of, in water used in manu- 
facture 248-249 

California, sketch map of part of 16 

Campbell's ranch, precipitation at 311 

Campo, precipitation at 303-304 

Carbonate, effects of, in water used in manu- 
factures 249 

Cardiff, municipal wells of 170-171 



Page. 

Carroll dam site, precipitation at 307 

Caves produced by wave erosion, plate show- 
ing 22 

Chambers, Alfred A., work of 19 

Charges, fixed, for pumping plants. 274-276 

Chico formation, nature and distribution of. . 51-52 

Chihuahua Mountain, precipitation at 294 

Chloride, effects of, in water used in manu- 
factures 249-250 

Chocolate Creek, precipitation at 302 

Chollas Heights, precipitation at 311 

Chubbic, Benjamin, well of 198 

Chula Vista, section near 63 

Chula Vista Oil Co., logs of test wells, Nos. 

1-4 of 64-65 

Chula Vista oil well, log of 66 

Chula Vista terrace, ground water in 181-187 

Clark oil well, log of 55 

Classification of water, standards for 223 

Cliffs, sea, development of 22-23 

Coast line, irregularity of 21 

nature and development of 22-25 

Coastal belt, general features of 21-22 

Color, effects of, in water used in manufactures 248 

Corrosion in boilers, causes of 239-240 

Cottonwood, precipitation at 309 

Cottonwood Creek, course and valley of 39 

Cretaceous formations, water from, quality 

of 253-255 

Cretaceous metamorphism, outline of 74 

Cretaceous peneplanation, outline of 74-75 

Cretaceous rocks, caves in sea cliffs of, plate 

showing 22 

description of 51-52 

Crystalline rocks, water in 189-190 

Cuyamaca, precipitation at 296 

Cuyamaca Mountain, view from 35 

Cuyamaca reservoir, evaporation from 101-102 

D. 

Dall, W. H., fossils determined by 53, 54, 

59-60,62,63,69 

Damrons, precipitation at 290 

Deadmans Hole, precipitation at 291 

Dehesa, precipitation at 311 

Dehesa Valley, fluctuation of water table in, 

diagrams showing 134 

Delmar , sections near 53, 54 

well near 178 

Depletion of the reservoirs, amount of... 146-149 

Descanso, precipitation at 299 

Descanso Valley, precipitation at 310 

Dick, Robert, log of well of 62 

Dickerson, R. E., cited 56-57 

Dickson, J. C, wells of 197-198 

315 



316 



INDEX. 



Page. 

Dike, diabase, near La Jolla, extent of 23 

diabase, near La Jolla, plate showing 22 

porphyritic, cutting Tertiary sediments, 

plate showing 50 

Dinsmore, S. C, work of 19 

Discharge of pumping plants, method of 

measuring 265-266 

Diverting dam, precipitation at 303 

Domestic use, water for, bacteria in 224-225 

water for, physical qualities of 224 

substances dissolved in 224, 225-227 

yield required 142-143 

Drainage areas above gaging stations, map 

showing In pocket. 

Drainage systems, peculiarities of 39-40 

Drawdown, effect of, on yield of wells 156-157 

See also "Water table, lowering of. 

Duke, W. D., well of 200-201 

Dulzura, precipitation at 309 

Duty of water, mode of estimating 152 

E. 

Eagles Nest, precipitation at 294 

E ast Cuyamaca, precipitation at 303 

El Cajon, precipitation at 301 

El Cajon (city), precipitation at 310 

El Cajon Valley, description of 44, 45-46 

plate showing 39 

precipitation at 305 

wells in residuum in 231-202 

El Cajon Valley and vicinity, map of, show- 
ing water-bearing formations and 

observation wells In po::ket. 

Electricity, advantages of, for pumping 

plants 284-285 

Ellis, John L., well of 198 

Elsinore, precipitation at 297-298 

Encinitas, sections near 54,55 

wells near 170-171 

Engines, gasoline, advantages of, for pumping 

plants 281-285 

Eocene series, rocks of 53-57 

Equivalents, convenient 287 

Erosion by floods, efficiency of 33 

by waves, caves produced by. plate 

showing 22 

by winds 29-30 

in arid regions, plate showing 38 

Escondido, precipitation at 296-297 

wells in residuum at and near 197- 199 

Escondido ditch, precipitation at 297 

Escondido Mutual Water Co.'s canal near Nel- 
lie, discharge of, from 1904 to 

1915 97, 98 

Escondido Valley description of 44 

Evaporation, losses of ground water by 146 

Evaporation from soil, determination of . . . 104-105 
from water surfaces, records of 99-104 

F. 

Fairbanks, H. W., cited 37, 40-41, 57-58 

Fallbrook, precipitation at 305-306 

wells in residuum at and near 196 

Fallbrook Plain, basin south of 43-44 

description of 43 

Fault exposed at the Himalaya mine, plate 

showing 38 



Page. 

Faulting, effects of 37 

Field work, record of 19 

Fissures, water in 189-190 

Flint, A. A., well of 199-200 

Flood flow of rivers, duration of 144 

Flow of streams, duration of 136-138 

Foaming in boilers, causes of 240-241 

Formations, highland, groups of 189 

water-bearing, map showing 106 

comparison of waters from 250-258 

Fossils, occurrence of . . . . 53, 54, 59-60, 62, 63, 64, 69, 73 

Foster Valley, fill of 120 

Fruit-trees, yield of ground water required by. 142 

Fulton, Charles L., cited 100 

Fulwiler, J. A., well of 196-197 

G. 

Geologic history, outline of. 74-76 

Geology of the area 50-76 

publications on 288-289 

Gold, placer, occurrence of 40-41 

Goodyear, W. A., cited 35 

Granite, fluctuation of water table in, dia- 
grams showing 192 

decomposed, fluctuation of water table in 134 

prevalence of 191 

Gravels, placer, origin of 28-29 

Tertiary, ground water in 177 

Grigsby's ranch, precipitation at 310 

H. 

Harm, method used by, for calculating aver- 
age annual precipitation 85 

Harvey ranch, precipitation at 308 

Hauck,Ferdinand, wells of 230 

Head against which a pump operates, method 

of determining 206 

Hemphill, Henry, fossils collected by 59-60 

Highland area, general features of 34-35 

Highland basins, general features of 41-43 

Historical geology, outline of 74-76 

Hollywood, log of well near 62 

Hot Springs Mountain, precipitation at 297 

Hydrogen sulphide, effects of, in water used 

in manufactures 250 

I. 

Idyllwild, Riverside County, precipitation at. 313 

Igneous rocks, nature and distribution of 71-73 

Industrial uses, miscellaneous, effects of im- 
purities in 246-250 

Interference of wells, instances of 184-185 

Iron, effects of, in water used in manufac- 
tures 248 

Irrigation, census data on t 15 

fitness of waters for 258 

method of distributing water for 199-200 

water for, alkali in 229-238 

with ground water, beginning of 15-17 

cost of pumping for 274-276, 277-279 

yield required for 142 

J. 

Jaeger, R. J., test of pumping plant of 271-272 

Jamacho Valley, fluctuation of water table in, 

diagrams showing 134 

Jamul ranch, precipitation at 309 



INDEX. 



317 



Page. 

e Jamul Store, precipitation at 305 

Jamul Valley, features of 47 

Japatul, precipitation at 312 

* Johnson, J., jr., test of wells of 159 

I Jones, W. H., wells of 203 

Julian, precipitation at 295-296 

"K. 
Kitchen Valley, precipitation at 311 

II L. 

\ La Jolla, coast line near 24 

La Jolla Indian Reservation, precipitation at 304 
\ La Mesa, end of flume near, precipitation at. 302 

" La Mesa dam, precipitation at 306 

; La Mesa reservoir, evaporation from 101-104 

1 La Posta, precipitation at 312 

La Presa, precipitation at 311 

Lacustrine deposits, nature of 70 

Lagoons, features of 22 

Laguna, precipitation at 304 

Laguna ranger station, precipitation at 311 

' Lakeside, precipitation at 301 

' Landslide in wall of Mission Valley, plate 

showing 33 

Lanier, L. K., log of well of 62 

Larsen, E . S . , igneous rocks described by 73 

( Lauterbaughs, precipitation at 313 

Layne, W. R., workof 20 

Leakage into surrounding formations, loss of 

ground water by 148-149 

Lee, D. L., work of 19 

Lehner, George, well of 197 

Linda Vista Mesa, age of 27-28 

ridges on 30 

well on 178 

west edge of, plate showing 23 

, Linda Vista terrace, map showing erosional 

. features of 28 

mounds on, plate showing 30 

Linda Vista Terrace district, general condi- 
tions of 177-178 

water in 178-188 

Lo Tengo Oil Co., log"of well of 67 

Los Coches Creek, precipitation at 302 

Los Padres ranch, precipitation at 307 

I Los Penasquitos Creek, well on 171-172 

i Loss of ground water, relation of replenish- 
ment to 149 

i Lower Otay reservoir. See Otay reservoir, 
lower. 

"Lows," paths of 76-77 

Lyon Peak, precipitation at 309 

I Lyon Valley, precipitation at 309 

M. 
McGonigle Canyon, wells in 171 

Magnesium, effects of, in water used in man- 
ufactures 248-249 

Map of El Cajon Valley and vicinity, show- 
ing water-bearing formations and 

observation wells In pocket. 

of Mission Valley, showing water-bearing 

formations and observation wells 106 
of part of California showing areas treated 
in Water-Supply Papers relating 
to ground water 16 



Map of San Diego quadrangle showing marine 
terraces and marine soundings 

In pocket, 
of San Dieguito Valley, showing locations 
of observation wells and gaging 

stations 108 

of San Luis Rey and Santa Margarita 
valleys showing water-bearing 
formations and observation wells 

In pocket, 
of San Pasqual and Santa Maria valleys, 
showing water-bearing forma- 
tions and observation wells 108 

Map of southern part of San Diego Bay region, 
showing water-bearing forma- 
tions and wells 106 

of the San Diego County area, showing 
topography and location of wells 

In pocket, 
preliminary geologic, of western part of 

San Diego County In pocket. 

showing precipitation and drainage areas 

above gaging stations In pocket. 

topographic, of part of La Jolla quad- 
rangle, showing erosional features 28 

Marlor,D. T., wellof 198 

Marron Valley, precipitation at 309 

Matagual, precipitation at 295 

Material containing ground water 110-111 

Mendenhall Valley, precipitation at 293 

Merrill, F. J. H., cited 72 

Mesa Grande, precipitation at 293 

Mesas, difficulty of irrigating 258 

location of 21 

Metamorphic rocks, nature and distribu- 
tion of 71-73 

Metamorphism, Cretaceous, outline of 74 

Meyer, A. C, wellof 197 

Miller, Joseph, test of pumping plant of 272-273 

well of 202 

Miner's inches, equivalent of 287 

Miocene series, rocks of 57-68 

Miramar , precipitation at. 312 

wells near 174, 178 

Mission Bay, features of 24 

Mission Valley, description of 32 

floor and fill of 114-116 

fluctuation of water table in, diagrams 

showing In pocket. 

ground water in 115-116 

landslide in wall of, plate showing 33 

longitudinal profile of, showing fluctua- 
tion of water table In pocket. 

map of, showing water-bearing formations 

and observation wells 106 

section across, showing fluctuation of 

water table 132 

sections of wells in, plate showing 116 

tests of wells in 159, 160-161 

wells south of 174 

Modigajuat, precipitation at 312 

Monkey Hill, precipitation at 290 

Monte pumping plant, plan of, plate showing 132 

Morena dam, precipitation at 304 

Mounds, origin of 29-30 

on Linda Vista terrace, plate showing. . . 30 



318 



INDEX. 



Page. 

Mountains, effect of on precipitation 87-88 

general relations of 36 

origin of 33-37, 48-50 



National City, section from, to Tia Juana 
Valley, showing fluctuations of 

water table In pocket. 

Nellie, precipitation at 293 

Nestor, wells near 1S6-187 

Nestor terrace, fluctuation of water table in, 

section showing In pocket. 

ground water in 181-187 

Nobles mine, precipitation at 311 

North San Diego, section near 62 

O. 

Oak Grove, precipitation at 293 

Oceanside, development of the seashore near. 22-23 

precipitation at 298 

Oranges, duty of water for 193 

Orcntt, C. R., cited 59-60 

Organic matter, effects of, in water used in 

manufactures 250 

Oscillation of the coastal belt 21-22, 24, 75-76 

Otay, precipitation at 307 

Otay Mesa, wells on 179 

Otay reservoir, lower, precipitation at 307 

upper, evaporation from 102-104 

Otay Valley, description of 32 

development of 33 

Otay Valley and vicinity, fluctuation of water 

table in, sections showing. . In pocket. 

P. 
Padre Barona Valley, features of 47 

wells in residuum in 202-203 

I'ala conglomerate, nature and origin of 70 

plate showing 50 

Palm City, wells near, interference of 184-185 

Pamo, precipitation at 291 

Pamo camp, precipitation at 30S 

Pebbles , acctimulation of, by waves 23-24 

deposited by stranded seaweed, plate 

showing 23 

Peneplanation, Cretaceous, outline of 74-75 

Perforation of well casings, method of 164 

Petrero, precipitation at 310 

Physiography of the area 1 20-50 

publications on 288-289 

Pine Hills Hotel, precipitation at 305 

Pine Mountain, precipitation at 295 

Pine Valley Creek, features of 39 

Plant efficiency, definition of 287 

Pleistocene series, rocks of 69-70 

Pliocene series, rocks of 57-68 

Point Loma, development of 24 

location of 21 

log of well at 61 

precipitation at 307 

Porosity, effect of, on yield of wells 156 

of the valley fill, determination of .. . 121-123 
Potability of water, effects of substances in 

solution on 226-228 

Poway , precipitation at 298-299 

Poway conglomerate, nature and origin of. . . 67-68 
Poway grade,origin of 27 



Poway Mesa, age of 27-28 

development of 28 

Poway terrace, map showing erosional fea- 
tures of 28 

Poway Valley, description of 44-45 

wells in residuum in 199-200 

Power for pumping plants, selection of 284-285 

input of, method of measuring 267 

Pratt, Dr. , wells of 196 

Precipitation above gaging stations, map 

showing In pocket. 

annual, variation in, plate showing 86 

average annual, method used by Hann 

for calculating 85 

average depth of, required to produce 

run-off 97-99 

distribution of, by time 85-87 

geographic 87-90 

effect of mountains on 87-88 

index of, at nine control stations 84 

influence of topography, location, and al- 
titude on , diagrams showing 88 

on drainage basins of streams in San 

Diego County 95-96 

quantities of, required to produce flood 

run-off in typical streams 93-94 

records of 290-313 

method of averaging 83-84 

summary of 79-81 

relation of run-off to 90-99 

summary of 99 

where and by whom recorded 77-78, 82-83 

Publications consulted 288-290 

Tueblo farm, precipitation at 312 

Puerta La Cruz, precipitation at 291 

Pump efficiency, definition of 267 

Pumping, cost of, for irrigation 274-276, 277-279 

cost of, yield of ground water limited by. 143 

lowering of water level by 155 

Pumpingplant, Monte,plan of, plate showing. 132 

Pumping plants , census data on 15 

efficiency of 277 

fixed charges for ,. 274-276" 

piping and connections for 285-286 

publications consulted on 289-290 

selection and installation of machinery 

of 279-286 

tested, maps showing locations of. . 106,inpocket. 

tests of, methods used in 265-267 

purpose of 264-265 

results of 267-274 

Pumps, centrifugal, description of 282-284 

deep-well reciprocating, description of 282 

efficiency of 276-277 

power-plunger, description of 282 

selection and installation of 280-284 

Purpose of the investigation 19 

Q. 

Quality of ground water 222-263 

Quality of surface waters 259 

Quaternary period , events of 75-76 

rocks of. 68-71 

R. 

Rainfall, dispersal of . 76 

quantities of, available for absorption 193 



INDEX. 



319 



Page. 
Ramona, precipitation at 292 

wells in residuum at and near 200-201 

Rattlesnake Valley , precipitation at 312 

Recent series, deposits of 71 

Replenishment of ground water, method of 

computing 149-153 

relation of, to loss 149 

Reservoirs, depletion of, amount of 146-149 

replenishment of, computation of 143-146 

underground, utilization of 154 

Residuum, character of 191 

occurrence of 71 

water in, quality of 251-253 

sourcesof 193 

water table in 192,196-205 

»wellsin, fluctuation of 192 
methods of sinking 194-196 

yield of 193-194 

Return of water to streams, losses from reser- 
voirs by 147-148 

Richardson, C. M., test of pumpingplant of. 267-268 

test of wells of 159-160 

Ridges, ancient beach, origin of 30 

Riezebus, William, well of 198-199 

Rincon, precipitation at 306 

River valley, ancient, description of 40-41 

River valleys, descriptions of 38-41 

nature of - 21,22 

See also Valleys. 

Rivers, duration of flood flow of 144 

source of water in 108-109 

Rockwood ranch, precipitation at 308 

Rose Glen, precipitation at 292 

Rosedale, deep well near 180-181 

Run-off from drainage basins of streams in 

San Diego County 95-96 

relation of, to precipitation 90-99 

S. 

1 San Clemente Canyon, wells in 173-174 

San Diego, precipitation at 300-301 

test of city wells of 160-161 

wells east of 179-180 

San Diego Bay,features of 25 

vicinity of, fluctuation of water table in, 

diagrams showing 184 

plate showing sections of wells in 112 

i San Diego County, preliminary geologic map 

of western part of In pocket. 

San Diego County area, map of In pocket. 

San Diego formation, ground water in 181-187 

nature and origin of 58-67 

San Diego quadrangle, map of, showing 
marine terraces and marine 

soundings In pocket. 

San Diego River above diverting dam, run-off 
from and precipitation on drain- 
age basin of 95, 98 

at diverting dam, duration of flow of 137 

flood-flow period of 144 

precipitation required to produce 

flood run-off in 94 

at Mission dam, duration of flow of 138 

flood-flow period of 144 

San Diego River valley, description of 39 

lower, fluctuation of water table in 133 



Page. 

San Diego River valley, upper, fill of 119-120 

upper, fluctuation of water table in 133 

fluctuation of water table in, dia- 
grams showing 138 

longitudinal profile showing posi- 
tions of water table in 1914-15 

In pocket. 

plate showing section of wells in 120 

section across, showing fluctuation of 
water table and plan of pumping 

plant 132 

test of wells in 159 

San Dieguito River at Bernardo, duration of 

flow of 137 

at B ernardo, flood-flow period of 144 

San Dieguito Valley, description of 31, 38-39 

fill of 116 

fluctuation of water table in 134 

diagrams showing In pocket. 

map of, showing location of observation . 

wells and gaging stations 108 

San Elijo Lagoon, section of mouth of 54 

San Felipe, precipitation at 294 

San Felipe Valley, features of 48 

ground water in 206-208 

San Gabriel River above Azusa, run-off from 
and precipitation on drainage 

basin of 96 

San Jacinto, Riverside County, precipitation 

at 313 

San Luis Rey River above Pala, run-off from 
and precipitation on drainage 

basin of 95 

at Bonsall, duration of flow of 136 

flood-flow period of 144 

near Pala , annual discharge of 98 

duration of flow of 136 

flood-flow period of 144 

precipitation required to produce 

flood run-off in 93 

San Luis Rey Valley, description of 31, 38 

floor and fill of 116-117 

fluctuation of water table in 134 

diagrams showing In pocket. 

map of, showing water-bearing forma- 
tions and observation wells . .In pocket. 
San Onofre breccia, nature and relations of. . . 57-58 
San Onofre Hill district, water in rocks of. . 176-177 

San Onofre Hills, form and origin of 30-31 

San Pasqual Valley, fill of 120-121 

fluctuation of water table in 134 

diagrams showing In pocket. 

map of, showing water-bearing forma- 
tions and observation wells 108 

San Pedro formation, nature and occurrence 

of .*, 69-70 

San Vicente Creek, valley fill on ' 120 

Santa Fe ranch, precipitation at , 313 

Santa Margarita River valley after the flood of 

January, 1916, plate showing 32 

before the flood of January, 1916, plate 

showing 32 

description of 31 

fill of 117 

map of, showing water-bearing forma- 
tions and observation wells. .In pocket. 
Santa Maria Creek, course of 39 



320 



INDEX. 



Page. 

Santa Maria dam site , precipitation at 306 

Santa Maria Valley, description of 47 

map of, showing water-bearing forma- 
tions and observation wells 108 

Santa Ysabel, divide near, precipitation at . . 306 
Santa Ysabel Creek above Ramona, run-off 
from and precipitation on drain- 
age basin of 95, 98 

near Escondido and Ramona, duration 

of flow of 137 

near Ramona, flood-flow period of 144 

See also San Dieguito Valley. 

Santa Ysabel ranch, precipitation at 291 

Santa Ysabel River near Ramona, precipita- 
tion required to produce flood 

run-off in 93 

Santa Ysabel Store, precipitation at 292 

Scale, formation of, in boilers 239 

Schilling, precipitation at 303 

Scope of the investigation 18-19 

Screens, influence of, on yield of wells 157-158 

Scripps Biological Institute, precipitation at. 313 

Sea cliffs, plate showing 22, 23 

Second-foot, equivalents of 287 

Sedimentary formations, nature and succes- 
sion of 50-71 

Sedimentation, pre-Cretaceous, outline of.... 74 

Tertiary, period of 75 

Sentinel, precipitation at 292 

Skye Valley, precipitation at 310 

Sleppy, K. B., work of 19 

Snow, precipitation of 77 

Soils of the major valleys, origin of 109-110 

Soledad Canyon, wells in 172-173 

Soledad Mountain, location of 21,24 

Solids, total, in water, computation of 228 

Sonoras, nature of 77 

Sorrento, deep well at 180 

South Las Choyas Valley, log of L. K. 

Lanier's well in 62 

Specific capacity of formations, definition of. . 158 

range of 163 

Specific capacity of wells, definition of 158 

Spring Valley, well in 174 

Springs, analyses of waters from 260-263 

hot, in Warners Valley 205-206 

Storage of water, difficulties of 16 

Storms, duration, intensity, and total precip- 
itation of, in 1914-15, plate show- 
ing 86 

types of 76-77 

Stream, underground, belief concerning — 154-155 

Streams, duration of flow of 136-138 

principal, comparative discharge meas- 
urements of 145-146 

daily hydrographs of, in 1914-15. In pocket. 
Sulphate, effects of, in waters used in manu- 
factures 249 

Surface waters, quality of 259 

Surveys of the region, previous 17-18 

Suspended matter, effects of, in water used 

in manufactures 247 

Sutherland dam site, precipitation at 306 

Sweetwater dam, precipitation at 299 

Sweetwater Pass, precipitation at 305 

Sweetwater reservoir, evaporation from 99-101 



Page. 
Sweetwater River above Sweetwater dam, 
run-off from and precipitation on 

drainage basin of 95, 98 

at Sweetwater dam, precipitation re- 
quired to produce flood run-off in. 94 

near Descanso, duration of flow of 138 

flood-flow period of 144 

Sweetwater Valley description of. 32, 39 

AH of 114,119 

fluctuation of water table in, diagrams 

showing 134 

Sylvester, J. D., well of 199, 200 

T. 

Table Mountain, location and altitude of 27 

Talus, water in 190-191 

Tecate, precipitation at 310 

Terraces, development of 21, 22-23, 25-30 

marine, map showing In pocket. 

See also Mesas. 
Tertiary formations, water from, quality 

of 253-: 

Tertiary and older sedimentary formations, 

water in 1 75-188 

Tertiary period, eventsof 75 

rocks of 52-68 

Thunder showers, occurrence of 77 

Tia Juana oil well, log of 67 

Tia Juana River, possible course of 25 

Tia Juana Valley, description of 32 

floor and fill of 112-114 

fluctuation of water table in, diagrams 

showing In pocket. 

ground water in 113-114 

longitudinal profiles of, showing fluctua- 
tions of water table 132 

section from, to National City, showing 

fluctuations of water table. .In pocket. 

test of, well in 159-160 

wells in 186-187 

sections of, plate showing 112 

Transmission constant, definition of 156 

Transpiration, losses of ground water by.. . 146-147 
Tucker & Evans, test of pumping plant of. 270-271 

U. 

Underflow, loss of ground water by 148 

nature and rate of 155 

Uplift of the highland area 20 

Uplift, Tertiary, results of 75 

Upper Otay reservoir. See Otay reservoir, 

upper. 

Utilization of ground water, history of 15-17 

V. 

Valley Center, precipitation at 300 

Valley fill, nature and distribution of 71 

origin of 111-112,119 

water from, quality of 255-258 

Valleys, coastal, description of 107-108 

coastal, water-bearing fill of 111-118 

highland, description of 108 

water-bearing fill of 119-121 

major, descriptions of 31-32 

drainage of 106-109 

origin of 32-34 






INDEX. 



321 



Valleys, major, relation of, to adjacent areas 105-107 

soils of ----- 109-110 

surface waters in 108-109 

topography of 100-108 

vegetation of 110 

water in 106-166 

minor, description of 34 

fluctuation of water table in 134 

diagrams showing 168 

in the highland area, ground water in 175 

topography and fill of 174-175 

nature and distribution of 166-167 

of the coastal belt, ground water 

in 168-169 

topography and fill of 167 

water table in 168 

wells in 169-174 

See also River valleys. 
Van Houten, C. A., test of pumping plant 

of 268-269 

test of wells of 159 

Vegetables, yield of ground water required 

by 142 

Vegetation of the major valleys, nature of 110 

Verlaque, precipitation at 292 

Viejas, precipitation at 312 

Volcan Mountain, precipitation at 295 

W. 

Warner dam site, precipitation at 290 

Warner ranch house, precipitation at 294 

Warner Springs, precipitation at 294 

Warner summer road, precipitation at 291 

Warners, divid e near, precipitation at 306 

Warner's ranch, precipitation at 306 

Warner's Valley, description of 48 

hot springs in 205-206 

water level in test holes in 203-205 

Water-bearing formations in San Luis Rey 

Valley, map showing In pocket. 

* in San Pasqual Valley, map showing 108 

in Santa Margarita Valley, map show- 
ing In pocket. 

in Santa Maria Valley, map showing 108 
Water horsepower, formula for calculating 287 

method of determining . . , 266 

Water table, form and slope of 123-132 

fluctuations of , 132-141 

annual range of 132-136 

causes of 135-136 

diagrams showing.. 134, 138, 168, 184, 192, 
• in pocket, 
in Mission Valley, cross section show- 
ing 132 

in Mission Valley, longitudinal profile 

showing In pocket. 

in Tia Juana Valley, longitudinal 

profiles showing 132 

in upper San Diego River valley, 

cross section showing 132 

periodic 141 

sections showing In pocket. 

115536°— 19— wsp 446 21 



Page. 
Water table, fluctuations of, widest range of 134 
in upper San Diego River valley, longi- 
tudinal profile showing positions 

of, in 1914-15 In pocket. 

lowering of, by pumping 155 

observations of, in wells 124-131 

time required for, to reach maximum 

levels 138-141 

Wells, analyses of waters from 260-263 

casings used in 165-166 

cost of 165-188 

detailed records of 209-221 

fluctuations of, in residuum 192 

maps showing locations of . . 106, in pocket. 

methods of sinking 164-166, 187-188, 194-196 

observation, in San Dieguito Valley, map 

showing locations of 108 

in San Luis Rey Valley, map show- 
ing locations of In pocket. 

in San Pasqual Valley, map showing 

locations of 108 

in Santa Margarita Valley, map show- 
ing locations of In pocket. 

in Santa Maria Valley, map showing 

locations of 108 

observations of water level in 124-131 

sections of, in Mission Valley, plate show- 
ing 116 

in Tia Juana Valley, plate showing . . 112 
in upper San Diego River valley, 

plate showing 120 

in vicinity of San Diego Bay, plate 

showing 112 

showing average fluctuation of water 

level, locations of 135 

showing small fluctuation of water level, 

locations of 135 

showing wide fluctuation of water level, 

locations of 134 

sizes of, advantages of large and small . . 672 

tests of 186-187 

purpose and method of 158 

results from 159-161 

summary and discussion of 162-164 

yield of, conditions affecting 155-158 

Williams, W. E., test of pumping plant of. 269-270 

Willows, the, precipitation at 309 

Winds, desert, description of 29-30 

erosion by. 29-30 

Winetka Valley, precipitation at 309 

Witch Creek, precipitation at 292 

Woodward, A. W., wells of 201 

Woodward, W. E., wells of 201 

Y. 

Yield of ground water, average, definition of. . 142 

average, determination of 143-153 

safe, computation of 153-154 

definition of 142-143 

Yield of wells. See Wells, yield of. 

Young Men's Christian Association of San 

Diego, well of 179 



? 



ADDITIONAL COPIES 

OP THIS PUBLICATION MAY BE PROCURED FROM 

THE SUPERINTENDENT OF DOCUMENTS 

GOVERNMENT PRINTING OFFICE 

"WASHINGTON, D. C. 

AT 

$1.00 PER COPY 

A 



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JPPLY PAPER 446 PLATE II 




A, SH0WI1 



Scale ssopoo 



8 ioE 



5vu? intei^val 2 5 O feet . 
K/re is mjactn sect, Tevel. 

1919. 



SNYDER &BLACK..N.Y 



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EXPLANATIO^ 



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MAP OF THE SAN DIEGO * 



\REA, CALIFOR N i A , SH OWING TOPOGRAPH Y AND LOCATION OF WELLS -"-■ — 



7 



JPPLY PAPER 446 PLATE ID. 




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MAP OF SAN DIEGO QUADRANGLE, CALIFORNIA 
Showing marine terraoes and marine soundings 






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WATIiR SUPPLY PAPER 44S PLATE ! 



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MAP OF EL CAJON VALLEY AND VICINITY, CALIFORNIA 

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WATER-SUPPLY PAPER 446 PLATE XXV 




WATER-SUPPLY PAPER 446 PLATE XXX 




Feb.27, 1915 
Feb. 12,1915 
Mar.31, 1315 
July 31, 1915 
Feb.4,1915 

Jan. 3L 19/5 
Oct. 22, 1914 
Jan. 26,/ 9 15 



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DISTANCE, IN FEET AND MILES, FROM MISSION BAY 
LONGITUDINAL PROFILE OF MISSION VALLEY, SHOWING POSITION OF WATER TABLE IN DIFFERENT SEASONS OF THE YEAR, 1914-1915. 

(Red line B-B, Plate XXI) 



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LOXGITl'UIXAl 



DISTANCE,!*/ FEET AND M/LES, FROM OLD M/SS/ON DAM 

•IIOH1K OF SAN DIEGO KIM H VALLEY, SHOWING POSITION OF WATEB TABLE IN DIFFERENT SEASONS OF 111 I \ EAR, 
[Line B-B, Plate XXH) 






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Apr. 30, 1915 
June 30, 1315 
July 30, 1915 
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Plate XX) 



I 48,000 
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SNYOER & BLACK.N.Y. 



S GEOLOGICAL SURVEY 



DISTANCE, IN FEET AND MILES, FROM SOUTH SIDE OF TIA JUANA VALLEr 



W MM.' ,1 I'll Y J ' \ I ')'. f : I Hi I'l.MI'. WW 




FROM TIA JUANA VALLEY TO NATIONAL CITY, SHOWING FLUCTUATIONS OF WATER TABLE, SEASON 1914-1915. 

(Red line A-A, Plate XX) 



i.i .'I c. h v m'i;\t:y 



WELL O 61 

:or sec. 36, 77 19 S„ R. 2 W., 900ft N. of 
river. Drilled well 27 ft. deep,elevation 
58.10 feet 



WELL O 14-1 

,... T sec. I,TI9S,R.2 W.. 250 ft. N. of river 
Drilled well 6/ ft deepe/evation5493feet 



W.WV.S: SII'1'l.-i I'M'l.l: i Hi l-'I.A I 1-: XX.vYI 



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WELL O I40 

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WELL O 127 

M£.'/4sec.2X 19 S., R.2 WJOOftN.of river. 
Drilled well 72ft.deep,elevation ZS.SOfeet 





WELL O 130 
I E.'A- sec. Z,Z IS 5.,R. 2 W., in river channel, 
■age at bridge, elevation 25. 5 feet; elevation, 
if stream bed 21.0 feet 



TWPT 



Ju/y I Aug- 




DIAGRAM SHOWING 

FLUCTUATIONS OF WATER TABLE 

IN OBSERVATION WELLS 

IN TLA JUANA VALLEY 

1914-1915 

NOTE; Dotted I 



6 PLATE XXXDC 





U. S. GEOLOGICAL SURVEY 



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WATER-SUPPLY PAPER 446 PLATE XLI 



DIAGRAM SHOWING 

FLUCTUATIONS OF WATER TABLE 

IN OBSERVATION WELLS 

INSJ N PASQUALAND SAN DIEGUITO VALLEYS 

1912-1915 







, 



U. S. GEOLOGICAL SURVEY 










191* 
















WATER-SUPPLY PAPER 446 PLATE XI .n 




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DIAGRAM SHOWING 

FLUCTUATIONS OF WATER TABLE 

IN OB SERVATION W E L I , S 

IN SAN LUIS REY VALLEY 

1912 - 1915 









1 



U. & GEOLOGICAL SURVEY 



WATER-SUPPLY PAPER 446 PLATE XLIV 




DISTANCE FROM SAN D/EGO BAY, W FEET AND M/LES 

SECTIONS ACROSS OTAY VALLEY AND PARALLEL TO IT, SHOWING FLUCTUATIONS OF WATER TABLE, SEASON 19U-1915. 

(Red line D-D, Plate XX) 



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(Red line C-C, Plate XX) 



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